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ATH 2007-05-08 13:34

Do you save all the factors you find during sieving/P-1 in a "master" list?

hhh 2007-05-09 09:56

No, but in a master directory. There are stored all the incoming files, with filenames in a comprehensible format. Then, the smallset factors are imported into an Excel-spreadsheed,:blush: and treated afterwards to build the files.
Anybody who wants the factors can have them, but be aware that they come in three different formats, from Multisieve, gcwsieve and prime95, so treating them will require some manual work.

What was the purpose of your question exactly?

ATH 2007-05-09 13:00

I just kept a list of factors. I sieved all the cullen numbers 1 to 5M to 2.5G originally and might continue sieving the non-prime cullen numbers at some point.

hhh 2007-05-09 13:09

Just tell me what you need/want, and you get it. H.

ATH 2007-05-09 23:08

I was just interested in the factors you found during sieving/P-1. It doesn't matter I have to put it together from several files.

geoff 2007-05-16 22:30

I also think it would be good to have a list of factors available for download somewhere.

A list of the smallest known factor for each Cullen composite (not just those with prime exponent) might be of some interest to researchers in itself.

ATH 2007-05-17 00:36

I'm keeping a list like that, and thats why I want new factors for it.

hhh 2007-05-17 07:32

I will post every factor as well as the list with the smallest factor known once sieving is finished, so latest in about a month. OK?
Yours H.

ATH 2007-05-17 11:52

sure thanks.

ATH 2007-05-29 20:07

I originally sieved cullen numbers 1 ≤ n ≤ 5M up to 2.5G. Now I expanded to 1 ≤ n ≤ 10M and sieved up to 4G so far.

I also added a few of your factors that you posted in sieve reservation thread and will add rest when they are posted.

I currently have 9,693,872 factors plus the 14 known cullen primes, so 306,128 without factors. In my list the 14 cullen primes have PRIME instead of factor and the 306,128 unknowns just have the TAB after the n-value and nothing more.

[URL=""][/URL] (33.4 Mb)

I plan to sieve up to 5G in the next days, and then possibly sieve the prime n's only for 5M ≤ n ≤ 10M for your next range.

em99010pepe 2007-05-29 21:30

1 Attachment(s)
My cullen factors.

hhh 2007-05-30 06:48

I am currently sieving prime n up to 25M; with multisieve, I am at p=25M and about to change to the next gear, i.e. gcwsieve. From now on, progress should be very fast.

I will post the factors for the 5M-10M range later today, the only ones missing are those from the last not yet assigned P-1-ranges.

More information is to come; I need breakfast before;-o

ATH 2007-05-30 12:26

ok, I won't sieve prime n's then, but continue with my big range. I might expand to 25M as well then when I hit 5G for 0-10M.

hhh 2007-05-31 10:41

1 Attachment(s)
As promised (a little late, though) the factors found so far. The content is in no sense beautiful, the best thing to do is probably to export everything out of the spreadsheet. I hope you can use the data in a way or another. Yours H.

ATH 2007-05-31 22:31

Thanks alot for those factors.

After cleaning it up and removing duplicates and only keep lowest when 2 factors to same n, I came up with factors for 1,499 cullen numbers:


and 2 factors that didn't check out:

19698213427 is not a factor of 1624241*2^1624241+1
8241190129247 is not a factor of 1638701*2^1638701+1

ATH 2007-05-31 22:59

Nevermind it was a typo in database.xls altering the n-value:

19698213427 is a factor of 1632341*2^1632341+1 (instead of 1624241)
8241190129247 is a factor of 1638107*2^1638107+1 (instead of 1638701)

So the total is still 1,499 factors.

ATH 2007-07-07 13:02

I expanded my sieving to 1 ≤ n ≤ 25M and sieved up to 5.4 G with a total of 24.221.687 factors found (including all those you found in this project) + the 14 known primes leaving 778.299 (3.15%) unfactored.

Factors for 1≤n≤10M: [URL=""][/URL] (35 Mb)
Factors for 10M≤n≤25M: [URL=""][/URL] (51 Mb)

Sieve file in ABC format with remaining 778.299 unfactored: [URL=""][/URL] (2 Mb)

I'm taking a break awhile from sieving cullen's plus I'm going on vacation :) Good luck on the project.

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