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Old 2003-04-08, 04:30   #2
paulunderwood
 
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Sep 2002
Database er0rr

2·11·167 Posts
Default Re: What is the status of the search and another link

We are building on work done on primes of the form k*2^n-1 by Wilfred Keller et al:

http://www.prothsearch.net/riesel2.html

Therefore the known values of 'n' that make 3*2^n-1 prime are: 1, 2, 3, 4, 6, 7, 11, 18, 34, 38, 43, 55, 64, 76, 94, 103, 143, 206, 216, 306, 324, 391, 458, 470, 827, 1274, 3276, 4204, 5134, 7559, 12676, 14898, 18123, 18819, 25690, 26459, 41628, 51387, 71783, 80330, 85687, 88171, 97063, 123630, 155930, 164987

The domain for 'n' in this search is initially 191600-1000000. I started sieving with Paul Jobling's NewPGen on the 2nd of this month using a 1GHz Athlon. Eleven blocks of work (191600-300000) became available on the 5th. Of those, one was completed in a couple of days using a P4 and LLR. Three of us are currently processing five blocks. This leaves five blocks and already the sieve is approaching the point where I release some more for testing.

Unlike Mersenne primes these numbers don't have to have a prime binary length. They look like this in binary:

101
1011
10111
101111
10111111
etc
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