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 2017-12-18, 17:26 #386 MisterBitcoin     "Nuri, the dragon :P" Jul 2016 Good old Germany 2E216 Posts A few days ago PG found the mega prime Code: 273809*2^8932416-1  The prime is 2,688,931 digits long. The official letter
 2017-12-28, 09:52 #387 Jean Penné     May 2004 FRANCE 24×5×7 Posts Sierpinski odd n's testing Hi, k=9267 is now tested up to n = 8,806,303 (2,650,966 decimal digits) no prime, continuing... Best Regards, Jean
2018-01-06, 09:53   #388
MisterBitcoin

"Nuri, the dragon :P"
Jul 2016
Good old Germany

2×32×41 Posts

Quote:
 Originally Posted by Puzzle-Peter R2, k=9519 finished to 2^24. No prime. Base released. R366 will pick up some speed now...
I´ve made an sieve file for this sequence up to N=25M.
The calc prime results are looking good.

Code:
using base 2, sieve depth 50000000, and reading 781255 candidates from t17_b2_k9519.npg

expected # of primes: 1.7263706830854946
odds of at least one prime: 82.20709997186222%
(or, in other words) 1 in 1.2164399429517392 chance of at least one prime
on average, 1 in 452541.8600156512 candidates should be prime
I´ll input the file into yoyo@home. Not sure if yoyo is going with my pmax=25e15.

After the file is done, around 03/2018, I´ll go ahead and start some testing. Everyone is welcomed to support.

2018-01-06, 21:09   #389
gd_barnes

May 2007
Kansas; USA

11×929 Posts

Quote:
 Originally Posted by MisterBitcoin I´ve made an sieve file for this sequence up to N=25M. The calc prime results are looking good. Code: using base 2, sieve depth 50000000, and reading 781255 candidates from t17_b2_k9519.npg expected # of primes: 1.7263706830854946 odds of at least one prime: 82.20709997186222% (or, in other words) 1 in 1.2164399429517392 chance of at least one prime on average, 1 in 452541.8600156512 candidates should be prime I´ll input the file into yoyo@home. Not sure if yoyo is going with my pmax=25e15. After the file is done, around 03/2018, I´ll go ahead and start some testing. Everyone is welcomed to support.
Please be careful when taking on such large efforts. I seriously doubt that this is correct. Otherwise we would have easily found a prime already.

Are you sieving only the even n? If not, you are outside of the scope of the project.

The easiest way to accomplish sieving even n only for 9519*2^n-1 n=2^24 to n=25M is to sieve base 4 instead for half the n-range; that is sieve 9519*4^n-1 for n=2^12 to n=12.5M.

My guess is that at most, there is a 20% chance of prime for even n for n=2^24-25M. Are you certain that you really want to do this? It would be extremely low priority on our sieving needs at this point.

Last fiddled with by gd_barnes on 2018-01-06 at 21:19

2018-01-06, 22:32   #390
MisterBitcoin

"Nuri, the dragon :P"
Jul 2016
Good old Germany

2×32×41 Posts

Quote:
 Originally Posted by gd_barnes Please be careful when taking on such large efforts. I seriously doubt that this is correct. Otherwise we would have easily found a prime already. Are you sieving only the even n? If not, you are outside of the scope of the project. The easiest way to accomplish sieving even n only for 9519*2^n-1 n=2^24 to n=25M is to sieve base 4 instead for half the n-range; that is sieve 9519*4^n-1 for n=2^12 to n=12.5M. My guess is that at most, there is a 20% chance of prime for even n for n=2^24-25M. Are you certain that you really want to do this? It would be extremely low priority on our sieving needs at this point.
I did a file for 9519*2^n-1 and submitted it to yoyo.
But it looks like the number of expected primes was wrong, so I´m dropping this effort.

2018-01-07, 06:08   #391
gd_barnes

May 2007
Kansas; USA

11·929 Posts

Quote:
 Originally Posted by MisterBitcoin I did a file for 9519*2^n-1 and submitted it to yoyo. But it looks like the number of expected primes was wrong, so I´m dropping this effort.
I'm still not sure that you understand.

The number of expected primes that you came up with is likely correct for ALL n but that is not what CRUS needs. You would need to sieve only even n. Sieving 9519*4^n-1 accomplishes that. Plenty of primes have already been found for base 2 k=9519 odd n. 9519*2^1-1, 9519*2^11-1, and 9519*2^15-1 are all prime and those are just the smallest 3 primes.

Regardless the effort is apparently not what you expected so it's best to drop it at this point. Few people want to run tests that take more than 1 day each.

Last fiddled with by gd_barnes on 2018-01-07 at 06:10

2018-01-16, 17:13   #392
Puzzle-Peter

Jun 2009

2·5·67 Posts

Quote:
 Originally Posted by gd_barnes Regardless the effort is apparently not what you expected so it's best to drop it at this point. Few people want to run tests that take more than 1 day each.
I do enjoy those long tests, so I started a sieve for n=2^24 to 2^26.

2018-01-16, 18:54   #393
MisterBitcoin

"Nuri, the dragon :P"
Jul 2016
Good old Germany

2·32·41 Posts

Quote:
 Originally Posted by Puzzle-Peter I do enjoy those long tests, so I started a sieve for n=2^24 to 2^26.
Send me that file, I´ll sieve up to 25e15.
Either in my "blog" or via the mail I pm´ed you.

 2018-01-16, 20:37 #394 VBCurtis     "Curtis" Feb 2005 Riverside, CA 2×5×19×23 Posts Looks like fun- I'll donate at least a haswell-core-month to LLR when the sieve file is ready.
2018-01-16, 20:47   #395
Puzzle-Peter

Jun 2009

29E16 Posts

Quote:
 Originally Posted by MisterBitcoin Send me that file, I´ll sieve up to 25e15. Either in my "blog" or via the mail I pm´ed you.
Ist this deep enough? You were planning to go to 25e15 for N=25M. This sieve file goes more than twice as high.

2018-01-16, 22:28   #396
MisterBitcoin

"Nuri, the dragon :P"
Jul 2016
Good old Germany

10111000102 Posts

Quote:
 Originally Posted by Puzzle-Peter Ist this deep enough? You were planning to go to 25e15 for N=25M. This sieve file goes more than twice as high.
I can also extend the search limit. Since it´s done with yoyo@home I can go as high as you´d like to have it. :)
You might also ask PG, so far I know they did some sieve files with way deeper P´s than yoyo@home would possibly do.

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