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-   -   The "Hey YOU" Thread (https://www.mersenneforum.org/showthread.php?t=18489)

wblipp 2013-07-25 01:01

This thread is for attempts to contact and/or inform other factordb users. Be aware the other users may not read this forum, or even know of it's existence.

kar_bon 2013-07-29 07:57

The "Hey YOU" Thread
 
To the guy who's doing n^m-1 (thounsands of small composites with n ~ 6- to 15-digit numbers and m ~ 5- to 17-digit exponent number):

Example:
The [url=http://www.factordb.com/index.php?id=1100000000626395150]C79=4545240977...71<79>[/url] is the composite part of (30488817170364239412727^5-1)/5796234755344305420995084262210186.

The quotient 5796234755344305420995084262210186 was not fully factored in FactorDB (just done it) so the 30488817170364239412727^5-1 wasn't, too.

The problem:
If the C79 factors to Px * Py the n^5-1 remains not fully factored in the FactorDB and someone (if >= 70 digits) has to do this factorisation although it could have been done if the factors were inserted to the n^5-1 and not to (n^5-1)/x!

This x sometimes contains greater factors which are not known to FactorDB to the originally n^5-1 value.

Please insert all new factors found to the n^5-1 value instead of (n^5-1)/x!


Another Example:
[url=http://www.factordb.com/index.php?id=1100000000627313897]C79[/url] is part of 14103553^17-1, this is a C122 with a C96!
So there's a small chance, that someone is doing the C79 while someone else tries factoring the C96 at the same time!

chris2be8 2013-07-29 17:13

I'm running scripts on two of my older systems to factor small numbers in factordb. They download random_composites.txt and factor everything they can from it (using SNFS if possible). But they just return:
(line from random_composites.txt)=p1*p2*p3 etc.
Is that going to cause this problem? If so what should the script do? I'm factoring hundreds of numbers per day so manual intervention is impossible.

The jobs are usually quick enough that collisions with someone else doing the number at the same time are rare.

Chris

wblipp 2013-07-29 19:37

[QUOTE=kar_bon;347675]To the guy who's doing n^m-1[/QUOTE]

That's probably the oddperfect project - at least when n and m are both prime. "Usually" (p^q-1), (p^q-1)/(p-1) and (p^q-1)/((p-1)*a) are in synch, all showing the same final composite. Once in synch, they stay in synch with any new factor showing up in all three forms. From time to time I push factors into factordb to increase the likelyhood of synchronization. It sounds like I need to do that for the batch of numbers that we are currently checking to see if additional factors are known.

wblipp 2013-08-20 13:57

To the guy who is entering lots of Homogenous Cunninghams (a^n+b^n, a, b, n small) - are you aware that when n has an odd divisor k, (a^(n/k)+b^(n/k)) is an algebraic divisor of your number?

The small end of the unfactored composites list is currently swamped with your numbers, many of which could be reduced under the automatic 70 digit limit by informing the factordb of these algebraic factors. For example, I just cleared 651^28+127^28 by telling the factordb about 651^4+127^4. You can load thousands of these factors quickly using the Report Factors page with lines like

651^28+127^28 = 651^4+127^4
(651^33+74^33) = (651^11+74^11) (651^3+74^3)

BudgieJane 2013-08-28 22:50

[QUOTE=wblipp;350229]To the guy who is entering lots of Homogenous Cunninghams (a^n+b^n, a, b, n small) - are you aware that when n has an odd divisor k, (a^(n/k)+b^(n/k)) is an algebraic divisor of your number?
[/QUOTE]
Yes, thanks.

[QUOTE]
The small end of the unfactored composites list is currently swamped with your numbers, many of which could be reduced under the automatic 70 digit limit by informing the factordb of these algebraic factors. For example, I just cleared 651^28+127^28 by telling the factordb about 651^4+127^4. You can load thousands of these factors quickly using the Report Factors page with lines like

651^28+127^28 = 651^4+127^4
(651^33+74^33) = (651^11+74^11) (651^3+74^3)[/QUOTE]

Sorry about that. I'm working on (a) stopping so many getting on there at any one time, and (b) clearing them up.

Are there any instructions for how to use FactorDB and how FactorDB works? I've had a good look around and can't find any.

henryzz 2013-08-28 22:52

[QUOTE=BudgieJane;351192]Are there any instructions for how to use FactorDB and how FactorDB works? I've had a good look around and can't find any.[/QUOTE]
Not really. We are available for questions though.

cubaq 2016-03-16 14:44

I am surely newby, and has some simple question:

- what will happen after my number receive C* from factordb.com/search.

wblipp 2016-03-17 03:13

[QUOTE=cubaq;429318]what will happen after my number receive C* from factordb.com/search.[/QUOTE]

factordb is a resource to collect known factorizations and primality proofs.

If your composite is under 70 digits, the factordb workers will factor it. This usually happens in seconds to minutes.

Above 70 digits it will sit there until somebody factors it. There are people that donate their resources to factor the smallest numbers. This usually factors numbers into the low 90 digits, and has occasionally factored everything into the high 11x level. You can see how this stands by going to the bottom of the status page and clicking on "Distribution of composite numbers."

Beyond that, your composite will sit there until someone gets interested enough to devote the resources to factor it. If you are the only person interested, that mean until you factor it.

PawnProver44 2016-04-10 04:00

[QUOTE=wblipp;429396]factordb is a resource to collect known factorizations and primality proofs.

If your composite is under 70 digits, the factordb workers will factor it. This usually happens in seconds to minutes.

Above 70 digits it will sit there until somebody factors it. There are people that donate their resources to factor the smallest numbers. This usually factors numbers into the low 90 digits, and has occasionally factored everything into the high 11x level. You can see how this stands by going to the bottom of the status page and clicking on "Distribution of composite numbers."

Beyond that, your composite will sit there until someone gets interested enough to devote the resources to factor it. If you are the only person interested, that mean until you factor it.[/QUOTE]

It is very useful for submitting primes about 5,000 digits. Is there any way i can "Organize a list" of random long primes of requested size?

wblipp 2016-04-11 00:55

[QUOTE=PawnProver44;431189]Is there any way i can "Organize a list" of random long primes of requested size?[/QUOTE]

You can use [URL="http://factordb.com/listtype.php?t=4"]this page[/URL] to get a list of primes starting at any particular size. You will need to do the trimming to exactly that size yourself and supply your own randomization.

chris2be8 2016-07-16 15:51

I've started running a script to go through the numbers with status unknown in factordb and add algebraic factors if factordb doesn't know about them. I *think* I've added long enough delays between requests to stop it overloading factordb. Is one request per second reasonable?

It'll probably take more than 6 months to go through all 41 million such numbers. So far I'm partly factoring about 9% of them.

When it's finished I could run it against composites with no known factors. I'd need to update it to stop it trying to add too many factors that are already known though.

Does anyone think they would find this useful?

Chris

chris2be8 2016-09-06 16:04

I decided to stop it once I'd reached 60,000 digit numbers. The tally is:

20,817,600 numbers checked.
1,023,341 numbers at least partly factored.
1,538 ended up fully factored.

There are probably some duplicates in there though.

I'll now start running against composites with no known factors. Which will take a few months. But should have more numbers end up fully factored, at least to start with.

Chris

henryzz 2016-09-07 09:56

[QUOTE=chris2be8;441740]I decided to stop it once I'd reached 60,000 digit numbers. The tally is:

20,817,600 numbers checked.
1,023,341 numbers at least partly factored.
1,538 ended up fully factored.

There are probably some duplicates in there though.

I'll now start running against composites with no known factors. Which will take a few months. But should have more numbers end up fully factored, at least to start with.

Chris[/QUOTE]

I assume that you are checking if a number would have algebraic factors even if the number has already had small factors removed.

chris2be8 2016-09-07 16:01

Correct. Eg: [code]
(6827^48+1)/29605130633466729757863645596968113368259830758158964079481474144706 (record 211, match 60) has 1 factor 6827^16+1
In postFactors url = http://factordb.com/index.php?id=1100000000585123211, factors = 6827^16+1
#### http://factordb.com/index.php?id=1100000000585123211 is fully factored ####
1 factor already known by factordb for record 211 (match 60)
[/code]
Chris

chris2be8 2016-10-21 20:30

Another "feature" I've just found, [url]http://factordb.com/listtype.php?t=3[/url] says you can skip a maximum of 50000 numbers. If you ask it to skip more it only skips 50000 numbers. So if there are more than 50000 numbers with a given number of digits the rest can't be displayed.

That caught my script out. There are more that 50000 309 digit numbers in factordb. And it didn't notice that when it asked to skip 50012, 50112, 50212, etc numbers it was always getting the same list of numbers. And I didn't notice for a few hours either.

I've patched the script to skip to the next number of digits once it's checked the first 50100 numbers (I read 100 at a time so can get that far). Which at least lets it carry on.

Chris

EdH 2016-10-21 21:20

[QUOTE=chris2be8;445517]Another "feature" I've just found, [URL]http://factordb.com/listtype.php?t=3[/URL] says you can skip a maximum of 50000 numbers. If you ask it to skip more it only skips 50000 numbers. So if there are more than 50000 numbers with a given number of digits the rest can't be displayed.

That caught my script out. There are more that 50000 309 digit numbers in factordb. And it didn't notice that when it asked to skip 50012, 50112, 50212, etc numbers it was always getting the same list of numbers. And I didn't notice for a few hours either.

I've patched the script to skip to the next number of digits once it's checked the first 50100 numbers (I read 100 at a time so can get that far). Which at least lets it carry on.

Chris[/QUOTE]
Would you be able to access 4900 more if you asked for 5000 and pulled out sections of 100 for your script?

chalsall 2016-10-21 21:33

[QUOTE=EdH;445520]Would you be able to access 4900 more if you asked for 5000 and pulled out sections of 100 for your script?[/QUOTE]

Not quite sure what you are trying to say there.

Does this translate into mass or money?

chris2be8 2016-10-22 17:26

[QUOTE=EdH;445520]Would you be able to access 4900 more if you asked for 5000 and pulled out sections of 100 for your script?[/QUOTE]

Yes, it is possible and I've updated my script to do it. But there are more than 55000 309 digit numbers in factordb so I still can't get at the rest.

Chris

xilman 2016-10-22 17:54

[QUOTE=chris2be8;445541]Yes, it is possible and I've updated my script to do it. But there are more than 55000 309 digit numbers in factordb so I still can't get at the rest.

Chris[/QUOTE]Writing from a position of profound ignorance here: is it possible to ask for all 309-digit numbers which begin with (or end with) a specific string of digits?

EdH 2016-10-22 18:55

[QUOTE=chris2be8;445541]Yes, it is possible and I've updated my script to do it. But there are more than 55000 309 digit numbers in factordb so I still can't get at the rest.

Chris[/QUOTE]
I notice, looking at the distribution graph, that there is a spike that goes up a couple thousand above 55000 right at 309 digits. There is another larger area up a few digits that encompasses a range above 55000.

I guess we'll just have to factor some of those 309 digit composites...

EdH 2016-10-22 20:56

Chris,

Depending on how bad you want those "invisible" 309s, this might allow you to find them. It's not very professional and I'm not sure it will even work, but let me know if it's of use:

bash script:
[code]
#!/bin/bash/

IFS="
"

# index of last known** 309 digit composite
index=1100000000871347918
let indexEnd=${index}+100

while [ $index -lt $indexEnd ]
do
seek=http://factordb.com/index.php?id=$index
wget $seek

exec <${seek:20}
while read line
do
case $line in
*"query"*) comp1=${line};;
esac
done

rm ${seek:20}

comp2=${comp1##*=}
composite=${comp2:1:${#comp2}-3}
compLength=${#composite}

if [ $compLength -eq 309 ]
then
echo $index >>indices309
fi

let index=${index}+1
done
[/code]** By known, I'm referring to the last visible one initially. Then it can be changed to the new last known (now 1100000000871348012) after a run.

It can put a bit of a pull on the db, but here is what it returned using the values in the above example:
[code]
1100000000871347918
1100000000871347925
1100000000871347943
1100000000871347973
1100000000871348009
1100000000871348011
1100000000871348012
[/code]I think, other than the first one, these are all currently unavailable to you.

edit: This version works on my Fedora 22 under its bash version. There might be slight differences in the string manipulations. I hope you can catch and fix those, if necessary.

edit: Also note there is a file removal line that deletes the page retrieved by the wget line. If that removal line is of concern, it can be commented or removed and no files will be deleted.

Ed

henryzz 2016-10-22 21:33

I was thinking about running a script to ecm them. I realised though that it is quite possible that they are rsa 1024 bits.

xilman 2016-10-23 13:55

[QUOTE=henryzz;445558]I was thinking about running a script to ecm them. I realised though that it is quite possible that they are rsa 1024 bits.[/QUOTE]If you would like to run ECM on 309-digit composites I could provide you with 21 of them. You are rather more likely to find factors than you would from RSA public moduli.

The numbers in question come from the generalized Cullen and Woodall tables. Smaller numbers, limited to C300, are presently loaded into the ECMNET server running at 109.109.168.71:8194.

What the heck, let's give you the 21 anyway.
[code]
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[/code]
You should use B1 at least 43M and preferably 110M or 260M as they have all been completed well into a t50 test.

Have fun!

EdH 2016-10-23 14:19

xilman,

Just curious, but are your 21 in the db presently? I would query it to see, but then they would be, whether or not they had been.

xilman 2016-10-23 14:35

[QUOTE=EdH;445594]xilman,

Just curious, but are your 21 in the db presently? I would query it to see, but then they would be, whether or not they had been.[/QUOTE]I don't know for certain but it seems very likely that they will be.

EdH 2016-10-23 15:22

[QUOTE=xilman;445595]I don't know for certain but it seems very likely that they will be.[/QUOTE]
A non-committal test appears to show the first one is, anyway:

[URL]http://www.factordb.com/index.php?id=1100000000593028069[/URL]

chris2be8 2016-10-23 15:56

[QUOTE=EdH;445555]Chris,

Depending on how bad you want those &quot;invisible&quot; 309s, this might allow you to find them.[/QUOTE]

I don't want them that badly. All my script is doing is looking for numbers that have algebraic factors and telling factordb about any factors it didn't know of. So I'm happy enough to check just the numbers I can easily find.

Your script goes through them by index. Which isn't guaranteed to find them all unless I check every index higher than the last 309 digit one I can see. Which would also find a lot of partly or fully factored numbers.

Chris

chris2be8 2016-10-23 16:00

[QUOTE=xilman;445542]Writing from a position of profound ignorance here: is it possible to ask for all 309-digit numbers which begin with (or end with) a specific string of digits?[/QUOTE]

I don't know of any way to do it. I'm screen-scraping [url]http://factordb.com/listtype.php?t=3[/url] and that doesn't offer any option to do that.

Chris

EdH 2016-10-23 16:59

[QUOTE=chris2be8;445606]...
Your script goes through them by index. Which isn't guaranteed to find them all unless I check every index higher than the last 309 digit one I can see. Which would also find a lot of partly or fully factored numbers.

Chris[/QUOTE]
True! I hadn't considered the "other than composite" returns. I suppose I could build that check in also, but as you point out, all indexes above the highest known would be quite a load.

henryzz 2016-10-23 18:06

I was thinking of ecm to remove small primes and bring it under 50000 composites. An initial test on the first 5000 makes it look like 5% can be removed fairly easily. How many do we need to remove?

schickel 2016-10-23 18:53

[QUOTE=EdH;445594]xilman,

Just curious, but are your 21 in the db presently? I would query it to see, but then they would be, whether or not they had been.[/QUOTE]The way to check that is go ahead and query. If it's new, you get the * indicator that it was freshly added. If there's no star, check the "More information" field to see approximately when the record was created.[QUOTE=EdH;445600]A non-committal test appears to show the first one is, anyway:

[URL]http://www.factordb.com/index.php?id=1100000000593028069[/URL][/QUOTE]For example, this shows:[code]
[B]Create time[/B]

Between March 17, 2013, 5:05 pm and March 17, 2013, 5:20 pm[/code]I don't know if you can pick that up programmatically though.

EdH 2016-10-23 20:50

[QUOTE=henryzz;445618]I was thinking of ecm to remove small primes and bring it under 50000 composites. An initial test on the first 5000 makes it look like 5% can be removed fairly easily. How many do we need to remove?[/QUOTE]
From the distribution graph, I had estimated ~2000, but someone else might want to check that.

EdH 2016-10-23 20:56

[QUOTE=schickel;445622]The way to check that is go ahead and query. If it's new, you get the * indicator that it was freshly added.
...[/QUOTE]But, if I were to query, it would make the query itself a moot point, since any number queried would be in the db. I was merely thinking of looking at the ones that were, but didn't want to add any to the db for only that reason.

schickel 2016-10-23 21:55

[QUOTE=EdH;445631]But, if I were to query, it would make the query itself a moot point, since any number queried would be in the db. I was merely thinking of looking at the ones that were, but didn't want to add any to the db for only that reason.[/QUOTE]Oh, sorry. I thought you wanted to know if they had been inserted previous to your querying them. I would probably assume if the numbers have been around any significant length of time, they'll most likely be in there because someone will have looked them up.

There would actually be a way to not insert them if you could get close to your limit of page hits; after you hit the limit, it will show numbers that you query as not in the DB but also not insert them. Kind of useless, since you usually want to be inserting them anyway.

EdH 2016-10-23 22:27

[QUOTE=schickel;445633]Oh, sorry. I thought you wanted to know if they had been inserted previous to your querying them. I would probably assume if the numbers have been around any significant length of time, they'll most likely be in there because someone will have looked them up.

There would actually be a way to not insert them if you could get close to your limit of page hits; after you hit the limit, it will show numbers that you query as not in the DB but also not insert them. Kind of useless, since you usually want to be inserting them anyway.[/QUOTE]
Thanks! although it would be minuscule in the overall scheme, I didn't want to add to the already too-large number of 309 digit composites. I think the only times I hit my limit were when running yafu.pl and the limit cleared rather quickly.

Although xilman's numbers have significance, I don't like adding numbers that have no other significance than my curiosity.

henryzz 2016-10-23 22:32

[QUOTE=EdH;445630]From the distribution graph, I had estimated ~2000, but someone else might want to check that.[/QUOTE]

I should be able to remove that. I spending around a second ecming each of the 55000 numbers accessible. The factor rate should be over 5% based upon experiments. I am hoping for 3000 factors. Of course the few digits before will need redoing as well as my factors will leave smaller composites. Assuming one factor per number it will be necessary to go back around 30 digits. Currently my best factor is 25 digits. That will probably increase.
I might try and run this sort of ecm from the smallest numbers upward and see how far I can get. I would imagine I would get a higher factor rate normally than 309 digits due to rsa composites.

henryzz 2016-10-24 10:43

[QUOTE=henryzz;445635]I should be able to remove that. I spending around a second ecming each of the 55000 numbers accessible. The factor rate should be over 5% based upon experiments. I am hoping for 3000 factors. Of course the few digits before will need redoing as well as my factors will leave smaller composites. Assuming one factor per number it will be necessary to go back around 30 digits. Currently my best factor is 25 digits. That will probably increase.
I might try and run this sort of ecm from the smallest numbers upward and see how far I can get. I would imagine I would get a higher factor rate normally than 309 digits due to rsa composites.[/QUOTE]

Half done and 3700 factors. Largest 31 digits

EdH 2016-10-24 14:33

[QUOTE=henryzz;445659]Half done and 3700 factors. Largest 31 digits[/QUOTE]
And, yet, the distribution graph remains unchanged...

henryzz 2016-10-24 14:41

[QUOTE=EdH;445668]And, yet, the distribution graph remains unchanged...[/QUOTE]

I haven't submitted yet.

EdH 2016-10-24 22:52

I am wondering... how is/will henryzz's work affect chris2be8's work?

Also, I see a lot of the following:
[code]
[URL="http://www.factordb.com/index.php?id=1100000000874739246"][COLOR=#002099](137^104*17^51*226^14*188+1)/1434648233765[/COLOR][/URL]
[/code]Are these numbers formatted this way by the db for display, or are they entered into the db from a particular project?

Is there a reason for the spike at ~309 digits and the even larger amount at around 480-500 digits?

schickel 2016-10-25 01:04

[QUOTE=EdH;445713]I am wondering... how is/will henryzz's work affect chris2be8's work?

Also, I see a lot of the following:
[code]
[URL="http://www.factordb.com/index.php?id=1100000000874739246"][COLOR=#002099](137^104*17^51*226^14*188+1)/1434648233765[/COLOR][/URL]
[/code]Are these numbers formatted this way by the db for display, or are they entered into the db from a particular project?

Is there a reason for the spike at ~309 digits and the even larger amount at around 480-500 digits?[/QUOTE]I think someone is dumping numbers in. Don't know if they're from a "useful" project or not. I was looking at the PRPs over the weekend and thinking about clearing out the backlog <3000 digits again and saw a whole crap load of 19--3x digit primes appear (>25 in pretty much all the bins for size). They promptly vanished, but whenever I see that it concerns me that they're dumping number in faster than the prime-check workers can clear them. I would have to assume that the sudden spike in composites springs from the same effort.

The spikes in the "counts by type" graph do kind of look like someone is searching numbers near "rounds": decades, centuries, etc. Prime search of some kind?

chris2be8 2016-10-25 15:47

[QUOTE=EdH;445713]I am wondering... how is/will henryzz's work affect chris2be8's work?

[/QUOTE]

It won't affect me at all. I've checked for algebraic factors up to 324 digits, finding smallish factors by ECM won't create any more algebraic factors.

If it makes some more 309 digit numbers accessible I could do a special run to check them for algebraic factors. All I need to know is what range to search in factordb and when to start.

Chris

henryzz 2016-10-25 20:38

My work is submitted. Doesn't seem to have brought it below 550k numbers at 309 digits.

EdH 2016-10-26 01:28

[QUOTE=henryzz;445767]My work is submitted. Doesn't seem to have brought it below 550k numbers at 309 digits.[/QUOTE]
The spike has shown no noticeable decrease. I wonder if the graph is current and if the labels are true. Now, my curiosity is piqued...

chris2be8 2016-10-26 15:43

It's brought some numbers I hadn't checked into the accessible range, so I'll check them for algebraic factors. Thanks for the help.

Chris

EdH 2016-10-26 22:15

In my earlier limited view of the last visible 309 digit composites, it appeared that they were provided in index order. However, a more broad inspection has shown that the case, in fact, is different. This makes my earlier script even less valuable...

(I know, some of you are asking, "How could it possibly be less valuable than it was?":smile:

chris2be8 2017-07-17 16:20

[QUOTE=chris2be8;441740] I'll now start running against composites with no known factors. Which will take a few months. But should have more numbers end up fully factored, at least to start with.
[/QUOTE]

Finished at 60,000 digits (there are not many composites with no known factors in the range where status unknown isn't checked).

The final tally:
52363400 checked.
1809152 at least partly factored.
127059 fully factored.

And there will be some more where I lost the response from factordb. And some fully factored by factordb after I reduced them to under 70 digits.

I was originally planning to run it once a year. But since it took a year to run I'll wait a few weeks before restarting it against numbers with status unknown.

Chris

swellman 2017-08-18 00:08

U208052 is found to be C - now what?
 
I searched the forum for an answer to this, but could not find anything. Apologies if this question has been dealt with before.

While exploring the [url=http://home.earthlink.net/~elevensmooth/Progress.html]ElevenSmooth site[/url], we were inspired to plug the full M3326400 into factordb for grins, and found the largest factor is listed as [url=http://factordb.com/index.php?id=1100000000495254317]U208052[/url]. Ryan Propper ran 50 Miller-Rabin tests on it (using his own code), and all came back "not a prime". While this result certainly isn't shocking, it would settle the question of whether any further work is warranted on this particular cofactor. And no, no one is going to do much with a composite so large. But the issue is still open.

Is there a process to request to convert a U to a C without actually finding a factor? Presumably someone must verify compositeness on a trusted system with vetted software, correct?

Or are it's factors already known, hidden in plain sight? I'm not ashamed to admit I don't fully understand all the intertwined branches of so large (and smooth!) a Mersennes number. Any advice would be greatly appreciated.

Has anyone heard from William of ElevenSmooth lately?

axn 2017-08-18 03:29

[QUOTE=swellman;465812]Ryan Propper ran 50 Miller-Rabin tests on it (using his own code), and all came back "not a prime". [/quote]
WTF? Why? 1 negative result is sufficient.

[QUOTE=swellman;465812]While this result certainly isn't shocking, it would settle the question of whether any further work is warranted on this particular cofactor.[/quote]
As such, there is no efficient way to ECM _just_ this cofactor. You can use P95 to ECM its parent (2^1663200+1)

[QUOTE=swellman;465812]Is there a process to request to convert a U to a C without actually finding a factor?[/quote]
Do you have a login for factordb? AFAIK, there used to be a feature for trusted users to manually change the status of a number (but it may have been removed). You could write to Syd. FTR, factordb will automatically do PRP test for numbers < 20k digits, and for numbers between 20k digits and x digits, users can "Assign" them for PRP test. I don't know what 'x' is, but obviously it is not big enough to cover this composite.

[QUOTE=swellman;465812]Or are it's factors already known, hidden in plain sight?[/QUOTE]
If someone knew additional factors of this number, presumably they would've reported it to factordb.

swellman 2017-08-18 10:54

[QUOTE=axn;465845]WTF? Why? 1 negative result is sufficient.[/quote]

50 instances launched in parallel. Saved days in the (very) off chance it was prime. Wasted 49 instances if it was composite. Flip a coin.

[quote]
As such, there is no efficient way to ECM _just_ this cofactor. You can use P95 to ECM its parent (2^1663200+1)[/quote]
Thanks. Never actually used P95 but maybe it's time.

[quote]
Do you have a login for factordb? AFAIK, there used to be a feature for trusted users to manually change the status of a number (but it may have been removed). You could write to Syd. FTR, factordb will automatically do PRP test for numbers < 20k digits, and for numbers between 20k digits and x digits, users can "Assign" them for PRP test. I don't know what 'x' is, but obviously it is not big enough to cover this composite.[/quote]

No, but I will pursue one. Is Syd the only person who can issue an ID? I sense he's pretty busy with RL these days.

[quote]
If someone knew additional factors of this number, presumably they would've reported it to factordb.[/QUOTE]

Agreed. I'm just unsure how the ElevenSmooth project was managed. There are about fifty composite cofactors (plus one unknown) listed in Factordb that do not appear on the 11S site. I'm assuming they're all interrelated, i.e. find a factor of a smaller composite on 11S and one of the bigger terms will also benefit when the factor is reported to fdb.

axn 2017-08-18 13:32

[QUOTE=swellman;465856]50 instances launched in parallel. Saved days in the (very) off chance it was prime. Wasted 49 instances if it was composite. Flip a coin.[/quote]
:rolleyes: To each their own, I say :smile:

[QUOTE=swellman;465856]No, but I will pursue one. Is Syd the only person who can issue an ID? I sense he's pretty busy with RL these days.[/quote]
Yes, Syd is the only admin. To get an id, you can use [url]http://www.factordb.com/login.php?register=1[/url]. But to get special privileges, you'll have to write to Syd.

[QUOTE=swellman;465856]Agreed. I'm just unsure how the ElevenSmooth project was managed. There are about fifty composite cofactors (plus one unknown) listed in Factordb that do not appear on the 11S site. I'm assuming they're all interrelated, i.e. find a factor of a smaller composite on 11S and one of the bigger terms will also benefit when the factor is reported to fdb.[/QUOTE]

The composite cofactors come from the algebraic factorization. As such there is no point in tracking them. Factordb allows it, so someone (possibly even william) must've entered them. And you're right, factordb stores them in such a way that factor reported for one number (say C) is automatically available for all numbers that have C as a composite cofactor.

schickel 2017-08-18 13:42

As of now, there is no interface for changing a number's status available anymore.

There was an option available to flip a number from C to P for a while, but bad things happened while it was there. Unfortunately Syd did not also provide an option to do the revse - flip a number from P to C - so it could be rechecked if a number was marked P in error.

swellman 2017-08-18 14:30

[QUOTE=axn;465860]
Yes, Syd is the only admin. To get an id, you can use [url]http://www.factordb.com/login.php?register=1[/url]. But to get special privileges, you'll have to write to Syd.

[/quote]

Thanks. From schickel's post after yours, it sounds like the special privileges thing has gone away but I then don't need/want it.

[quote]
The composite cofactors come from the algebraic factorization. As such there is no point in tracking them. Factordb allows it, so someone (possibly even william) must've entered them. And you're right, factordb stores them in such a way that factor reported for one number (say C) is automatically available for all numbers that have C as a composite cofactor.[/QUOTE]

Thanks. Will focus on the composites list on the 11S site, with reports of any factors found to be made to factordb of course.

swellman 2017-08-18 14:32

[QUOTE=schickel;465862]As of now, there is no interface for changing a number's status available anymore.

There was an option available to flip a number from C to P for a while, but bad things happened while it was there. Unfortunately Syd did not also provide an option to do the revse - flip a number from P to C - so it could be rechecked if a number was marked P in error.[/QUOTE]

No worries, we will have to do it the old fashioned way - split it with a hammer! A really big hammer...

firejuggler 2017-08-20 17:42

a c28 has been found

chris2be8 2017-09-30 16:35

Does anyone know who is adding lots of numbers like 485^1158-1 to factordb? They are appearing with status unknown faster than factordb can PRP test them.

It would be friendlier to tell factordb about the algebraic factors when they are added.

I've re-started my script to check numbers with status unknown for algebraic factors and add any factors it finds, working from 4000 digits upwards. But that's only a stopgap.

Chris

rcv 2017-09-30 18:55

[QUOTE=swellman;465856]I'm just unsure how the ElevenSmooth project was managed. There are about fifty composite cofactors (plus one unknown) listed in Factordb that do not appear on the 11S site. I'm assuming they're all interrelated, i.e. find a factor of a smaller composite on 11S and one of the bigger terms will also benefit when the factor is reported to fdb.[/QUOTE]

As you probably know, FactorDB does not have an inherent understanding of algebraic factorizations.

About five or six years ago there were many large ElevenSmooth numbers in FactorDB (i.e., numbers of the form 2^n+1, where n divides 1663200) where there were a handful of small prime factors and a handful of megacomposite factors. I attempted to work my way through the entire ElevenSmooth factorization tree to ensure that each number of those forms was the product of known factors and primitives.

Once "normalized", if that's the correct term, then "yes", a factor of a smaller primitive should appear in FactorDB's reported factorizations of the ancestors who were part of the "normalization" process. So, when you looked at 2^3326400-1, every "large" factor (whether prime or composite) represents the ultimate factor of one of the ElevenSmooth primitives. And that should remain the case as you continue to report factors.

However, if you were to look just outside the tree whose root is 2^3326400-1, you would find numbers where the primitives were not neatly separated. (Unless somebody else has undertaken a similar effort.)

jcrombie 2017-09-30 22:11

If you follow the way it's done on paper with the Cunningham project, then you significantly reduce the amount of storage required. Just store factors of primitives and recalculate on the fly when required. For 485^1158-1 we don't need to store anything, we could just refer to (485^579-1) and (485^579+1).

rcv 2017-10-01 09:19

[QUOTE=chris2be8;468897]Does anyone know who is adding lots of numbers like 485^1158-1 to factordb? They are appearing with status unknown faster than factordb can PRP test them.

It would be friendlier to tell factordb about the algebraic factors when they are added.

I've re-started my script to check numbers with status unknown for algebraic factors and add any factors it finds, working from 4000 digits upwards. But that's only a stopgap.

Chris[/QUOTE]
There are tens of thousands of these entries (perhaps hundreds of thousands) in the low range of the Unknown numbers. And most of the numbers I see are of the form a^b-1. (Although some are of the type of pattern used by our old friend, user cmd.)

The best thing we, as users, might do is to feed FDB with nice factor trees, starting with the algebraic (and occasional Aurifeuillean) *primitives*. Let's give our small factors *once* to the *primitives*, not to each of the 4000-digit numbers which might contain a smaller algebraic factor's primitive.

@Chris: I have (some) experience in teaching algebraic and Aurifeuillean factor trees to FDB. And I'm willing to help. Have you collected a list of base/exponent ranges involved?

Perhaps Markus should be contacted. Does he want the users to deal with this vandalism, or does he just want to expunge everything that came from the vandal's IP address?

chris2be8 2017-10-01 16:02

[QUOTE=rcv;468944] @Chris: I have (some) experience in teaching algebraic and Aurifeuillean factor trees to FDB. And I'm willing to help. Have you collected a list of base/exponent ranges involved?
[/QUOTE]

I don't need help, my script is adding the algebraic factors for all the a^b-1 numbers it finds. I just need to leave it running until it's gone through the range (it may take a few months but that's not a big problem).

The worse problem is numbers added as a string of digits, not an expression. I can't do anything useful with them.

Chris

rcv 2017-10-02 13:44

[QUOTE=chris2be8;468962]I don't need help, my script is adding the algebraic factors for all the a^b-1 numbers it finds. I just need to leave it running until it's gone through the range (it may take a few months but that's not a big problem).

The worse problem is numbers added as a string of digits, not an expression. I can't do anything useful with them.

Chris[/QUOTE]

Good luck, Chris. But I fear you will never catch up. Below is a sampling of every millionth ID. Number 900000000 was entered on February 2, 2017. Number 950000000 was entered on July 31, 2017. August and September exceed the number of entries from the previous 6 months, and a large majority of the newer entries are useless. It also appears the attacker is getting more and more bold, by adding additional classes of garbage numbers. Maybe factordb needs a "proof of work", as used in blockchains, to prevent entry of completely useless numbers at no cost to the attacker.

[CODE] id | status | length | number
---------------------+--------+--------+----------------------------------------------------
1100000000900000000 | P | 25 | 2894044212560751417491563
1100000000901000000 | FF | 29 | 17723754780876988611193626090
1100000000902000000 | FF | 47 |
1100000000903000000 | FF | 34 | 3703711103717039257039997037901243
1100000000904000000 | FF | 32 | 10119289550232258292275092014003
1100000000905000000 | | 999 | 10^998+22417453
1100000000906000000 | P | 990 | (10^999+2350097)/4675692609
1100000000907000000 | FF | 88 | 7587579601...33
1100000000908000000 | FF | 20 | 29980982030602115554
1100000000909000000 | | 1260 | (331^509-330^509)/266258864160225303711481
1100000000910000000 | FF | 86 | 7630323809...52
1100000000911000000 | | 981 | (10^1000+19914305)/61456116871205931585
1100000000912000000 | | 985 | (10^1000+21159213)/8859713393305073
1100000000913000000 | FF | 31 | 3384445114575424237319522118359
1100000000914000000 | | 996 | (10^998+22718615)/465
1100000000915000000 | FF | 91 | 2884806400...53
1100000000916000000 | FF | 72 | 9457045185...72
1100000000917000000 | CF | 989 | (10^1000+22752475)/618351983419
1100000000918000000 | CF | 996 | (10^998+22952639)/327
1100000000919000000 | FF | 89 | 1905597835...13
1100000000920000000 | CF | 1000 | 10^999+2940527
1100000000921000000 | | 997 | (10^998+23202343)/11
1100000000922000000 | FF | 24 | 738958854142100215398527
1100000000923000000 | P | 42 | 523733957716958045592126203718080743921067
1100000000924000000 | P | 19 | 3399717864477400603
1100000000925000000 | CF | 1000 | 10^999+3348527
1100000000926000000 | FF | 38 | 99067828970375937092137272115502781350
1100000000927000000 | FF | 39 | 457170293841184099267391620122028906997
1100000000928000000 | FF | 37 | 3535287024350672395176373260779520999
1100000000929000000 | FF | 42 | 903697840840887975256203596549395150175887
1100000000930000000 | FF | 34 | 2139275097021898619245674895609763
1100000000931000000 | P | 42 | 523733957716958045592126203718080653795603
1100000000932000000 | P | 67 | 5391799100...59
1100000000933000000 | P | 42 | 523733957716958045592126203718080618572879
1100000000934000000 | CF | 2103 | 147^970-2910^49
1100000000935000000 | FF | 19 | 1905410765229631181
1100000000936000000 | FF | 74 | 1003886521...03
1100000000937000000 | FF | 108 | 4614829803...53
1100000000938000000 | FF | 93 | 1809090588...99
1100000000939000000 | CF | 6940 | 5481049165...77
1100000000940000000 | FF | 36 | 347867765361036361764624535629476489
1100000000941000000 | FF | 30 | (21220877^5-1)/21220876
1100000000942000000 | FF | 67 | 1184136005...11
1100000000943000000 | P | 68 | 7938993865...03
1100000000944000000 | FF | 25 | 3239333001681515844589378
1100000000945000000 | FF | 60 | 6153072083...39
1100000000946000000 | FF | 61 | 2378811325...26
1100000000947000000 | P | 30 | 494389845534458673425627765851
1100000000948000000 | FF | 48 | (86572091^7-1)/86572090
1100000000949000000 | FF | 48 | (99993433^7-1)/99993432
1100000000950000000 | FF | 21 | 398088625655164941041
1100000000951000000 | FF | 19 | 3212823310200606061
1100000000952000000 | P | 20 | 17299984290333299741
1100000000953000000 | FF | 100 | (1703627^17-1)/1703626
1100000000954000000 | FF | 104 | (186769599624616303^7-1)/186769599624616302
1100000000955000000 | CF | 15445 | 383838^94+100^7722
1100000000956000000 | | 1147 |
1100000000957000000 | CF | 4799 | 2690921178...28
1100000000958000000 | CF | 5412 | 6330404541...82
1100000000959000000 | CF | 7895 | 1933564718...80
1100000000960000000 | | 3729 | 3536437129...07
1100000000961000000 | FF | 22 | 8556778994788983608339
1100000000962000000 | FF | 19 | 4463101554599774841
1100000000963000000 | FF | 95 | 9398250800...38
1100000000964000000 | CF | 169 | (103319887350439^13-1)/103319887350438
1100000000965000000 | CF | 6630 | 7327266194...64
1100000000966000000 | FF | 22 | 1933770422340354397873
1100000000967000000 | CF | 210 | (862168281937927060181^11-1)/862168281937927060...
1100000000968000000 | | 2761 | 4862298686...59
1100000000969000000 | | 3788 | 3273698841...31
1100000000970000000 | CF | 8836 | 1233587200...24
1100000000971000000 | CF | 9507 | 1278215347...01
1100000000972000000 | CF | 10891 | 3559572216...01
1100000000973000000 | CF | 11920 | 8251495301...01
1100000000974000000 | CF | 13215 | 1877872342...24
1100000000975000000 | CF | 7401 | 8612095055...95
1100000000976000000 | CF | 6343 | 1515948585...63
1100000000977000000 | CF | 1960 | 2114756195...08
1100000000978000000 | CF | 6093 | 1890258695...26
1100000000979000000 | CF | 3956 | 2428820789...02
1100000000980000000 | CF | 10848 | 4326617839...49
1100000000981000000 | CF | 6051 | 7216992894...24
1100000000982000000 | CF | 5224 | 1551^1637-1637^1551
1100000000983000000 | CF | 11635 | 100^5817+26426426487
1100000000984000000 | | 15956 | 1943^4852-4852^1943
1100000000985000000 | | 16356 | 2153^4907-4907^2153
1100000000986000000 | CF | 8315 | 2368^2464-2464^2368
1100000000987000000 | CF | 11181 | 2600^3274-3274^2600
1100000000988000000 | | 14924 | 2906^4309-4309^2906
1100000000989000000 | | 13442 | 3260^3826-3826^3260
1100000000990000000 | P | 83 | ((10000^23-1)/9999-23)/219978
1100000000991000000 | | 17087 | 4436^4685-4685^4436
1100000000992000000 | | 3761 | 1898868894...81
1100000000993000000 | | 27469 | 10^27468*3
1100000000994000000 | CF | 8191 | 6215179571...64
1100000000995000000 | FF | 111 | (17017017088^12+1)/3365480113673
1100000000996000000 | | 6534 | 1154974587...91
1100000000997000000 | | 6582 | 1339863569...07
1100000000998000000 | FF | 24 | 144072423069035225829571
1100000000999000000 | | 4901 | (305^1995-1)/2872101568838456354081604013959981...
1100000001001000000 | | 8496 | 3220548385...24
1100000001002000000 | | 8752 | 6973988096...92
1100000001003000000 | FF | 28 | 4229118215022440877033360947
1100000001004000000 | FF | 21 | 816231112528470350493
1100000001005000000 | | 9579 | 7936545539...88
1100000001006000000 | | 5374 | 699^1889-1
1100000001007000000 | | 10278 | 8333207607...73
1100000001008000000 | FF | 24 | 786330279963156175792691
1100000001009000000 | | 11836 | 821^4061-1
1100000001010000000 | FF | 20 | 69078720103003928483
1100000001011000000 | | 11537 | (1606^3610-3610^1606)/8055675728911642805770595...
1100000001012000000 | CF | 2110 | (955^718-1)/1634318514114083719803869396933
1100000001013000000 | FF | 24 | 205775303202062011657823
1100000001014000000 | FF | 65 | 2475787911...73
1100000001015000000 | FF | 24 | 628321561087304197773739
1100000001016000000 | | 13247 | 4819443453...83[/CODE]

cubaq 2017-12-26 12:42

retrieve HP10 last line
 
I'd like to retrieve last component (prime or composite) of base 10 sequence.
I know how to retrieve component using it's ID
(i.e. wget -q -b -w 5 'http://factordb.com/getnumber.php?id=1100000000733584886' -O "k49.txt")
, also I have found a way to retrieve elf file
(i.e. wget 'http://www.factordb.com/elf.php?seq=4788&type=1' -O alq_4788.elf)
, but the given example works only for Aliquot sequence. [I]No, &type=10 if not an answer.[/I]



Knowing that there is no documentation nor help option, I am asking:
How, using wget, retrieve ID, Number, or whole of last line, of base 10 sequence for given starting Number?


cubaq

EdH 2017-12-26 17:58

I'm not at all familiar with the home prime sequences, but the way I have found what to call in the past for other types, is to use the sequence page, ask for what I want and then study the address line in the page. As an example, to get the last line for home prime 49[SUB]10[/SUB], I would go to the HP[SUB]10[/SUB] sequence page enter 49, click on Show last element, then the Show button. This gives me an html page for the last element and the address for that page is in the address bar. I use tyhat address to d/l an html page and then harvest the ID from it. You can filter out the id using grep. See if this will get you what you want:

Example using 49[SUB]10[/SUB]:
[code]
wget "http://www.factordb.com/sequences.php?se=10&aq=49&action=last&fr=0&to=100" -O temphp.html
cat temphp.html | grep "showid"
[/code]You should be able to just sub in another number for the 49 in the example.

cubaq 2017-12-27 17:32

[QUOTE=EdH;474910]I'm not at all familiar with the home prime sequences, but the way I have found what to call in the past for other types, is to use the sequence page, ask for what I want and then study the address line in the page. As an example, to get the last line for home prime 49[SUB]10[/SUB], I would go to the HP[SUB]10[/SUB] sequence page enter 49, click on Show last element, then the Show button. This gives me an html page for the last element and the address for that page is in the address bar. I use tyhat address to d/l an html page and then harvest the ID from it. You can filter out the id using grep. See if this will get you what you want:

Example using 49[SUB]10[/SUB]:
[code]
wget "http://www.factordb.com/sequences.php?se=10&aq=49&action=last&fr=0&to=100" -O temphp.html
cat temphp.html | grep "showid"
[/code]You should be able to just sub in another number for the 49 in the example.[/QUOTE]





EdH,


Thank You very much, it works.


cubaq

EdH 2017-12-28 03:21

[QUOTE=cubaq;474992]EdH,


Thank You very much, it works.


cubaq[/QUOTE]
cubaq,

You're quite welcome. Glad it was what you wanted.

Ed

MisterBitcoin 2018-01-21 13:55

I was just taking a look into the "U" database and found a few [COLOR=Red]even[/COLOR] numbers, like [URL="http://factordb.com/index.php?id=1100000000817288834"]this[/URL].
Why are people uploading such numbers???

Any how, that a look at he amount of factors. :smile:

Just fully factored this even number: [URL="http://factordb.com/index.php?id=1100000000993422117"]10^100000*3 [/URL]
Someone just uploaded/checked this number...rly?

chris2be8 2018-01-22 17:31

That number is (10^100000-1)*2/9 and submitting that as a factor caused factordb to express it as that. Which saves a little bandwidth when looking at that page.

It also has a load of algebraic factors. Which is why it had so many small factors.

Chris


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