mersenneforum.org Riesel Primes k*2^n-1, k<300 [Was "k=1"]
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 2005-01-31, 17:42 #298 Harvey563     Apr 2004 101101112 Posts 91 riesel 91 is completed from 210000 to 300000, & prime for 245989! Harvey563
 2005-02-04, 01:32 #299 JCS   Nov 2004 Canada 1012 Posts Speaking of 91... Number 91 on the top 5000 is now 9*2^828709-1, which was proven prime earlier today! The k=9 search had been primeless for 6 months. Other recent finds: 129*2^292573-1 129*2^310619-1 129*2^314188-1 129*2^331384-1
 2005-02-05, 08:24 #300 Kosmaj     Nov 2003 2·1,811 Posts Congrats on a big, top-100 prime!
2005-02-05, 19:35   #301
Keller

May 2004

22·7 Posts

k=231 checked through n=310000 and is prime for
231*2^205017-1
231*2^224297-1
231*2^248359-1

Tests on 237 and 241 going on ...

EDIT: I stop 231 at n=310k

EDIT2: Attached is the sieve file with the numbers not tested yet to n=500k for k=231
Attached Files
 knpairs.txt (83.0 KB, 111 views)

Last fiddled with by Keller on 2005-02-05 at 19:40

 2005-02-13, 14:34 #302 Kosmaj     Nov 2003 70468 Posts Recent Progress Recently found primes and achieved limits are given below. k=55: 397941 [400000] k=71: 735802 prover's code L97 [736000] k=79: 369535 [370000] k=89: 369628 [380000]
 2005-02-13, 14:42 #303 Kosmaj     Nov 2003 E2616 Posts Is anybody interested in working on k=231 using pre-sieved values kindly provided by Keller above? If so, please announce your intentions in this thread. And please report primes (if any) by including "15k Search" in your prover's code.
 2005-02-14, 00:33 #304 lsoule     Nov 2004 California 23·3·71 Posts I'll take up the k=231 values and report back. (looks like n goes up to 400k and not 500k. I'll finish LLR up to 400k and sieve if it's still promising). Last fiddled with by lsoule on 2005-02-14 at 00:41
 2005-02-15, 13:47 #305 lsoule     Nov 2004 California 23×3×71 Posts Found a prime with 231: k=231: 345183 [complete to 318k]
 2005-02-15, 18:17 #306 Thomas11     Feb 2003 1,907 Posts k=75 Seems as if no one is currently looking at k=75 (formerly tested by keller up to n=250000). So, I'll take it a bit higher. Please let me know, if someone else has already choosen that k. -- Thomas11 By the way: k=29 is tested through n=1.2M now!
 2005-02-22, 02:25 #307 lsoule     Nov 2004 California 23·3·71 Posts 231*2^369583-1 is prime 231 is now complete to 400k and continuing. -Larry
 2005-02-28, 13:45 #308 robert44444uk     Jun 2003 Oxford, UK 2·7·137 Posts Nice big one Here is a note from Chris Caldwell's list: 220a 15*2^568780-1 171222 L52 2005 That is my second big prime from k=15 and my largest yet! Regards Robert Smith

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