2016-08-29, 18:57 | #1 |
I moo ablest echo power!
May 2013
5×349 Posts |
Double-Check
Could someone double-check the primality of 63998*297^21888-1?
It passes 3, 5, 7, and 11 Fermat PRP but fails the N+1 BLS test via PFGW. I'd appreciate someone else confirming one way or the other. |
2016-08-29, 19:15 | #2 |
"Serge"
Mar 2008
Phi(4,2^7658614+1)/2
9,431 Posts |
It is prime.
Code:
Using zero-padded FMA3 FFT length 28K, Pass1=448, Pass2=64, a = 3 ... Using zero-padded FMA3 FFT length 30K, Pass1=384, Pass2=80, a = 3 ... U((N+1)/11) is coprime to N! U((N+1)/3) is coprime to N! 63998*297^21888-1 is prime! (54129 decimal digits, P = 3) Time : 56.775 sec. Also, try LLR (and optionally, add FFT_Increment=1 (or 2, or 3) to llr.ini |
2016-08-29, 20:25 | #3 |
Jul 2003
2×5×61 Posts |
./sllr64 -q63998*297^21888-1
63998*297^21888-1 is prime! (54129 decimal digits, P = 3) Time : 198.176 sec. |
2016-08-29, 20:46 | #4 |
I moo ablest echo power!
May 2013
5·349 Posts |
Thanks to both of you. For full clarification, here's what I get with PFGW's "-tp" switch:
Code:
$ pfgw64.exe -f0 -a1 -tp -q"63998*297^21888-1" PFGW Version 3.7.10.64BIT.20150809.Win_Dev [GWNUM 28.6] No factoring at all, not even trivial division Primality testing 63998*297^21888-1 [N+1, Brillhart-Lehmer-Selfridge] Running N+1 test using discriminant 2, base 2+sqrt(2) 63998*297^21888-1 is composite (240.1252s+0.0018s) Last fiddled with by wombatman on 2016-08-29 at 20:47 |
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