20200409, 09:31  #1 
"Simon Josefsson"
Jan 2020
Stockholm
3×11 Posts 
How to request smallest >100M numbers for PRP?
I want to do PRPtesting of the smallest available firsttime >100M numbers. I have enabled the "get the smallest exponents" setting. However, when I configure my client for SrvrPO1=153, I received large >100M numbers such as M332380313. While fun to work on such a large number, I would prefer to work on the minimal >100M numbers. Is this possible? Or do I have to do manual assignment (which I've never tried before)?
Thanks, Simon 
20200409, 11:07  #2 
"Jacob"
Sep 2006
Brussels, Belgium
1,777 Posts 
The smallest Mersenne number with one hundred million digits (100M) is 2^{332 192 810}1 and obviously not a prime.
I think you confuse the exponent with the resulting number. 2^{100 000 000}1 has "only" thirty million, one hundred and three thousand digits (30 103 000). Jacob 
20200409, 11:11  #3  
"Simon Josefsson"
Jan 2020
Stockholm
3×11 Posts 
Quote:
Thank you  my mistake. /Simon 

20200409, 14:03  #4 
6809 > 6502
"""""""""""""""""""
Aug 2003
101×103 Posts
24012_{8} Posts 
There many of the lowest 100M digit numbers that have a known factor. Of those that don't, many have had a first time check PRP or LL. And then a bunch of the remaining are already assigned to people. When you tell Prime95 that you want to do PRP on numbers that large, PrimeNet will normally assign you the lowest available number.

20200504, 03:28  #5 
Sep 2017
USA
3·59 Posts 
I noticed a recent 100M digit PRP result (332356909) on the recently cleared list that a user presumably got through PrimeNet. It has only been TF'd to 77 bits and P1 factoring hasn't been done, but a user spent nearly 5,000 GhZ/days doing PRP.
Most of these low 100M digit exponents haven't had much of the early work done on them that helps weed out composite numbers. If you have access to a graphics card, you'll usually want to Trial Factor (TF) them to 80+ bits. Additionally, you'll want to perform P1 factoring before committing to a PRP. Good luck! Last fiddled with by Runtime Error on 20200504 at 03:31 Reason: spelling 
20200504, 15:51  #6  
"TF79LL86GIMPS96gpu17"
Mar 2017
US midwest
17E4_{16} Posts 
Quote:
https://www.mersenne.ca/exponent/332356909 says 1381 GhzDays for TF 77 to 81 bits. These are the cheap and plentiful Int32 TF GhzD (3072 GhzD/day on that gpu; 2.43% chance of factor found, or 5.4%/day for 0.45 days.) P1 says 172 GhzD, 5.59% chance of factor found to PrimeNet bounds, and those are the costly and less plentiful DPfloat kind. (~74GhD/day on an RTX 2080 Super gpu, or 2.4%/day for 2.3 days; I would actually use an AMD or low SP/DP ratio NVIDIA gpu or cpu instead. A Radeon VII could do it quickly, about 172/274 = .0.63 days) The PRP test recently reported is by xebecer, and is sort of special in that it is a type 4 residue and zero offset. That indicates it was performed using gpuowl between about V4.3 and V6.530c0508 which marked the return to type 1 PRP residues. It would require prime95 or mprime with residue type 4 specified for a PRP DC. The use of older versions of gpuowl that produce type 4 residues is discouraged, because
Last fiddled with by kriesel on 20200504 at 16:22 

20200506, 14:13  #7  
"TF79LL86GIMPS96gpu17"
Mar 2017
US midwest
2^{2}×11×139 Posts 
Quote:
In selecting singleprimalitytested exponents to LL DC or PRP DC in the range from current wavefront up to 200M exponent, I'm finding that many of those also lack sufficient TF or P1 or both. Last fiddled with by kriesel on 20200506 at 14:36 

20200508, 01:33  #8 
Sep 2017
USA
177_{10} Posts 
Ouch! At least you saved a DC though... congrats on the factor.
Last fiddled with by Runtime Error on 20200508 at 01:47 
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