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Old 2017-12-18, 17:26   #386
MisterBitcoin
 
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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



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Old 2017-12-28, 09:52   #387
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Default 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
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Old 2018-01-06, 09:53   #388
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Quote:
Originally Posted by Puzzle-Peter View Post
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.
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Old 2018-01-06, 21:09   #389
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Quote:
Originally Posted by MisterBitcoin View Post
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
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Old 2018-01-06, 22:32   #390
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Quote:
Originally Posted by gd_barnes View Post
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.
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Old 2018-01-07, 06:08   #391
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Quote:
Originally Posted by MisterBitcoin View Post
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
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Old 2018-01-16, 17:13   #392
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Quote:
Originally Posted by gd_barnes View Post

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.
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Old 2018-01-16, 18:54   #393
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Quote:
Originally Posted by Puzzle-Peter View Post
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.
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Old 2018-01-16, 20:37   #394
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Looks like fun- I'll donate at least a haswell-core-month to LLR when the sieve file is ready.
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Old 2018-01-16, 20:47   #395
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Quote:
Originally Posted by MisterBitcoin View Post
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.
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Old 2018-01-16, 22:28   #396
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Quote:
Originally Posted by Puzzle-Peter View Post
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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