mersenneforum.org Riesel Primes k*2^n-1, k<300 [Was "k=1"]
 Register FAQ Search Today's Posts Mark Forums Read

 2006-05-11, 17:58 #430 Cruelty     May 2005 65816 Posts k=25 status k=25 tested till n=700000. I'm still working on it
 2006-05-11, 20:38 #431 VBCurtis     "Curtis" Feb 2005 Riverside, CA 4,789 Posts Reserving k=197 and k=201. We'll test from 250k to 500k. k=127 is complete to 575k, sieved to n=1 million (p=800B). k=99 is complete to 260k, sieve at 1.9 trillion and counting. k=103 is sieved to 875B (up to n=500k), starting LLR now. -Curtis
 2006-05-31, 18:16 #432 lsoule     Nov 2004 California 110101010002 Posts End of the month status update and reservation End of the month status update: K current N 39 580k 69 735k 195 572k 231 858k Also, I'd like to reserve k=223 again and take it a little further past n=1M
 2006-06-03, 15:38 #433 Kosmaj     Nov 2003 2×1,811 Posts 20 K's for the 4th Drive We are about to start sieving the following 20 K's: 203, 205, 209, 211, 215, 217, 241, 245, 257, 259, 263, 265, 271, 275, 281, 283, 287, 293, 295, and 299 for the 4th Drive. We'll sieve in the n=100-600k range so that people who wish so can fill the holes on Keller's list. According to our stats and Prime Search's page (currently their web page is not on-line) all above K's have been checked to 230k, some to 250 and 260k and we'll concentrate our LLR efforts from respectively achieved limits. The only prime found beyond the reported limit is 245*2^238468-1 found by L118 in November 2005 (k=245 reportedly checked to 230k). Individual prime hunters for k*2^n-1, k<300 are directed to k's divisible by 3, k's less than 100 (specially for large exponents), and other available k's. I was thinking to also include k=91, 109, 139 and 173 but I didn't because k=91 has been tested to 300k, k=109 to 350k, and k=139 to 400k while k=173 is apperently beind tested by L99. The first 3 are available for individual prime hunters too. Please let me know if anybody has any objections/proposals regarding these 20 k's. Last fiddled with by Kosmaj on 2006-06-03 at 15:51
2006-06-03, 22:41   #434
MooooMoo
Apprentice Crank

Mar 2006

1C616 Posts

Update:

k=19 has been searched to n=660,000. Other than the prime reported in the "primes found" thread two weeks ago (for n=645,555), there are no other primes in this range.

I'll continue with this k, and the residues are attached below.
Attached Files
 lresults.txt (152.7 KB, 97 views)

 2006-06-05, 16:50 #435 Templus     Jun 2004 10610 Posts k=93 k=93 has been completed until n=400k, still in progress
2006-06-05, 20:42   #436
edorajh

Oct 2003
Croatia

1C816 Posts

Quote:
 Originally Posted by Kosmaj Prime Search's page (currently their web page is not on-line)
http://www.myjavaserver.com/~primesearch/

 2006-06-06, 08:45 #437 kar_bon     Mar 2006 Germany 1011010010012 Posts Status on k=209 i've reserved k=209 on prime search up to n=420.000. current n is 382.000 and no prime found yet.
 2006-06-06, 12:30 #438 Thomas11     Feb 2003 22·32·53 Posts k=155 k=155 has reached n=900k. But no primes found since n=500k. I'm continuing to n=1M...
 2006-06-08, 01:56 #439 Kosmaj     Nov 2003 2·1,811 Posts Thanks to everybody who replied. We have removed k=209 from our list, leaving it to Karsten. We added k=91 and k=109, so there are going to be 21 K's this time. Sieving is already under way. Our stats page is updated but the 21 K's are not marked yet.
 2006-06-10, 21:11 #440 R. Gerbicz     "Robert Gerbicz" Oct 2005 Hungary 22·367 Posts Hi all! Are you using newpgen for sieving? Because it doesn't observe algebraic factors, as I can see! So if k is a power of a number: k=a^d ( here a>1 and d>1 ) and n is divisible by d so n=s*d, then k*2^n-1 is composite, because it is divisible by a*2^s-1. In some cases it is a real improvement, but not very much, because in these cases you have got a very high chance that k*2^n-1 has got a "small" prime divisor, so newpgen will find it very quickly. Note that for some k, this is a zero improvement, for example if k=49 then 49*2^(2*s)-1 is divisible by 3, so all algebraic numbers are eliminated. For k=125=5^3 all 125*2^(5*s)-1 are divisible by 31. As I can see: up to 300 the suitable ( odd ) k values for real improvement: k=9, k=27, k=81, k=225, k=243 Last fiddled with by R. Gerbicz on 2006-06-10 at 21:19

 Similar Threads Thread Thread Starter Forum Replies Last Post CRGreathouse Number Theory Discussion Group 51 2018-12-16 21:55 URoy Miscellaneous Math 15 2016-11-17 22:52 Batalov And now for something completely different 12 2014-11-16 19:03 Kosmaj Riesel Prime Search 21 2012-09-14 09:51 nitai1999 Software 7 2004-08-26 18:12

All times are UTC. The time now is 23:20.

Mon May 17 23:20:25 UTC 2021 up 39 days, 18:01, 0 users, load averages: 2.27, 2.37, 2.39