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Search: Posts Made By: Jens K Andersen
Forum: Miscellaneous Math 2014-12-12, 17:22
Replies: 9
Views: 505
Posted By Jens K Andersen
You are missing 1, and it's more common to use 29...

You are missing 1, and it's more common to use 29 than -1. The usual form is (1,7,11,13,17,19,23,29 + 30*n). In case you don't know, 30 = 2*3*5 (product of the first three primes), and...
Forum: MattcAnderson 2013-11-01, 17:52
Replies: 119
Views: 17,250
Posted By Jens K Andersen
Here is a PARI/GP function to test whether a...

Here is a PARI/GP function to test whether a constellation is admissible:
admissible(v)=forprime(p=2,#v,if(#Set(v%p)==p,return(0)));1

This function returns the inadmissible primes:...
Forum: Software 2013-03-19, 02:29
Replies: 4
Views: 693
Posted By Jens K Andersen
What are you varying? If pn# is fixed then I have...

What are you varying? If pn# is fixed then I have an unpublished program APTreeSieve which can sieve any arithmetic progression up to at least 700000 digits. For k*274579#+-1 it's around 10 times as...
Forum: Puzzles 2013-03-04, 01:51
Replies: 40
Views: 3,487
Posted By Jens K Andersen
That Wikipedia article currently has 9.6 MB...

That Wikipedia article currently has 9.6 MB (http://en.wikipedia.org/wiki/Wikipedia:Database_reports/Talk_pages_by_size) of talk page discussions. Let's not compete with that here.
Forum: Math 2012-08-17, 21:24
Replies: 5
Views: 538
Posted By Jens K Andersen
I don't know what you mean here. The 76th prime...

I don't know what you mean here. The 76th prime is 383.
26 of the first 76 primes can be written on the form 2^m + 3^n:
2, 3, 5, 7, 11, 13, 17, 19, 29, 31, 41, 43, 59, 67, 73, 83, 89, 97, 113, 131,...
Forum: MattcAnderson 2012-07-29, 22:02
Replies: 119
Views: 17,250
Posted By Jens K Andersen
No. The source is adapted for each run. I...

No. The source is adapted for each run. I sometimes mail a version for a specific purpose like breaking a tuplet or Cunningham chain record.
Forum: MattcAnderson 2012-07-27, 01:57
Replies: 119
Views: 17,250
Posted By Jens K Andersen
I have confirmed the 52 smallest 12-tuplets in...

I have confirmed the 52 smallest 12-tuplets in http://oeis.org/A213601.
It took 10 minutes with my tuplet finder in C on a 2.4 GHz Core 2 Duo.
Forum: MattcAnderson 2012-07-27, 01:08
Replies: 119
Views: 17,250
Posted By Jens K Andersen
There are 20 or 21 examples of each pattern in...

There are 20 or 21 examples of each pattern in http://anthony.d.forbes.googlepages.com/ktmin.txt
Forum: MattcAnderson 2012-07-27, 00:58
Replies: 119
Views: 17,250
Posted By Jens K Andersen
In those tables he shows the first appearance to...

In those tables he shows the first appearance to be discovered and not the smallest appearance.
Forum: MattcAnderson 2012-03-16, 15:54
Replies: 119
Views: 17,250
Posted By Jens K Andersen
This gives no factor below 2111 for +1610: ...

This gives no factor below 2111 for +1610:
2383611079554*1327#+x+{0...3158}
I stop here. It was just a small exercise in futility. If we actually tried to find a 447-tuplet then there are better...
Forum: MattcAnderson 2012-03-16, 05:29
Replies: 119
Views: 17,250
Posted By Jens K Andersen
It looks like you made a mistake somewhere. There...

It looks like you made a mistake somewhere. There are smaller factors for +6 and +1836:
x =...
Forum: PrimeNet 2011-05-07, 03:20
Replies: 6
Views: 1,329
Posted By Jens K Andersen
See...

See http://primes.utm.edu/notes/faq/LongestList.html.
Considering the time to compute primes versus reading them from a disk or over the Internet, there is not much point in storing trillions of...
Forum: Chess 2011-03-23, 00:24
Replies: 266
Views: 24,029
Posted By Jens K Andersen
Don't expect to compute an exact number. ...

Don't expect to compute an exact number.
http://en.wikipedia.org/wiki/Chess#Mathematics_and_computers says:
The number of legal positions in chess is estimated to be between 1043 and 1047 (a...
Forum: Math 2011-02-14, 00:09
Replies: 9
Views: 2,702
Posted By Jens K Andersen
If a^(N-1)/2=-1 (mod N), then a^(N-1)=1 (mod N),...

If a^(N-1)/2=-1 (mod N), then a^(N-1)=1 (mod N), so N is a base-a Fermat prp by Fermat's little theorem (http://primes.utm.edu/glossary/xpage/FermatsLittleTheorem.html).

Proth's theorem gives a...
Forum: Factoring 2011-01-26, 17:17
Replies: 58
Views: 4,018
Posted By Jens K Andersen
I mailed this to Donovan Johnson in April 2009: ...

I mailed this to Donovan Johnson in April 2009:
I found the following probable primes with PrimeForm/GW.
They are all listed in http://www.primenumbers.net/prptop/prptop.php

Mersenne cofactors...
Forum: Factoring 2011-01-25, 22:52
Replies: 58
Views: 4,018
Posted By Jens K Andersen
Congratulations on beating my record! You can...

Congratulations on beating my record!
You can also try submitting to http://donovanjohnson.com/mersenne.html
Forum: Puzzles 2010-12-22, 22:07
Replies: 18
Views: 1,284
Posted By Jens K Andersen
Term 10, 22, 3270 were the only primes or prp's...

Term 10, 22, 3270 were the only primes or prp's up to 5000.
Forum: Puzzles 2010-12-22, 15:03
Replies: 18
Views: 1,284
Posted By Jens K Andersen
The next is a probable prime in term 3270: ...

The next is a probable prime in term 3270:
10^32700+((10^32700-1)/(10^3270-1)-10)/9 is Fermat and Lucas PRP! (534.7103s+0.0111s)
Forum: Puzzles 2010-12-22, 07:23
Replies: 18
Views: 1,284
Posted By Jens K Andersen
The below is based on proven primes. Most of the...

The below is based on proven primes. Most of the time was used on proofs. It only lists the last digits from the point where they deviate from the smallest possible number. After the first 5 terms...
Forum: Math 2010-12-16, 07:12
Replies: 61
Views: 8,665
Posted By Jens K Andersen
Getting back to the pointless computations...

Getting back to the pointless computations instead of discussing their pointlessness, at http://donovanjohnson.com/mersenne.html I think I found the 5 largest known probable Mersenne semiprimes :...
Forum: Puzzles 2010-06-22, 03:34
Replies: 10
Views: 809
Posted By Jens K Andersen
The earthquake revealing something lost or hidden...

The earthquake revealing something lost or hidden in the house was also my first thought. Or maybe his visiting mother in law was crushed to death and his wife would inherit a fortune. :devil:

The...
Forum: Information & Answers 2010-06-16, 01:16
Replies: 45
Views: 3,203
Posted By Jens K Andersen
Ah yes, the difference in my example was...

Ah yes, the difference in my example was apparently GFN recognition. Omitting division by 2 gives similar time difference:
C:\pfgw-work>pfgw -N -b7 base3b.txt
PFGW Version 3.3.3.20100325.Win_Stable...
Forum: Information & Answers 2010-06-16, 00:34
Replies: 45
Views: 3,203
Posted By Jens K Andersen
Some PFGW versions can make fast prp tests of...

Some PFGW versions can make fast prp tests of cofactors of optimized forms if the cofactor is written in a way recognized by PFGW. Compare these:

C:\pfgw-work>pfgw -N -b7 base3.txt
PFGW Version...
Forum: Miscellaneous Math 2010-05-28, 21:18
Replies: 40
Views: 14,055
Posted By Jens K Andersen
No, but I would sometimes prefer a change in...

No, but I would sometimes prefer a change in attitude towards people who don't live up to your expectations. This is an Internet forum, not an advanced math class. Experience indicates that when you...
Forum: Miscellaneous Math 2010-05-28, 14:21
Replies: 40
Views: 14,055
Posted By Jens K Andersen
I don't know whether it was first posted here or...

I don't know whether it was first posted here or moved but I saw it in Miscellaneous Math Threads which doesn't have high math expectations (although you appear to generally have higher expectations...
Showing results 1 to 25 of 230

 
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