Forum: Miscellaneous Math
2014-12-12, 17:22
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Replies: 9
Views: 967
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...
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Forum: MattcAnderson
2013-11-01, 17:52
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Replies: 160
Views: 55,865
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Forum: Software
2013-03-19, 02:29
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Replies: 4
Views: 936
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Forum: Puzzles
2013-03-04, 01:51
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Replies: 40
Views: 5,769
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Forum: Math
2012-08-17, 21:24
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Replies: 5
Views: 896
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,...
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Forum: MattcAnderson
2012-07-29, 22:02
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Replies: 160
Views: 55,865
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Forum: MattcAnderson
2012-07-27, 01:57
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Replies: 160
Views: 55,865
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Forum: MattcAnderson
2012-07-27, 01:08
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Replies: 160
Views: 55,865
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Forum: MattcAnderson
2012-07-27, 00:58
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Replies: 160
Views: 55,865
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Forum: MattcAnderson
2012-03-16, 15:54
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Replies: 160
Views: 55,865
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...
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Forum: MattcAnderson
2012-03-16, 05:29
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Replies: 160
Views: 55,865
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Forum: PrimeNet
2011-05-07, 03:20
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Replies: 6
Views: 1,902
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...
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Forum: Chess
2011-03-23, 00:24
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Replies: 266
Views: 46,111
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...
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Forum: Math
2011-02-14, 00:09
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Replies: 9
Views: 3,997
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Forum: Factoring
2011-01-26, 17:17
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Replies: 58
Views: 7,273
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Forum: Factoring
2011-01-25, 22:52
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Replies: 58
Views: 7,273
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Forum: Puzzles
2010-12-22, 22:07
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Replies: 18
Views: 2,336
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Forum: Puzzles
2010-12-22, 15:03
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Replies: 18
Views: 2,336
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Forum: Puzzles
2010-12-22, 07:23
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Replies: 18
Views: 2,336
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Forum: Math
2010-12-16, 07:12
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Replies: 61
Views: 15,158
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 :...
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Forum: Puzzles
2010-06-22, 03:34
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Replies: 10
Views: 1,268
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Forum: Information & Answers
2010-06-16, 01:16
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Replies: 45
Views: 6,738
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...
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Forum: Information & Answers
2010-06-16, 00:34
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Replies: 45
Views: 6,738
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...
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Forum: Miscellaneous Math
2010-05-28, 21:18
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Replies: 40
Views: 18,434
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...
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Forum: Miscellaneous Math
2010-05-28, 14:21
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Replies: 40
Views: 18,434
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