Added [URL="https://primes.utm.edu/primes/page.php?id=134739"]134739[/URL] : 471*2^22204781 (668434 digits)

Max found:
877*2^19277131 is prime 
Max found:
771*2^19335431 is prime 859*2^19352991 is prime 
Max found:
765*2^19373641 is prime 743*2^19383441 is prime 
Max found:
607*2^19425651 is prime 603*2^19440861 is prime 
Max found:
949*2^19447411 is prime 
Max found:
675*2^19490151 is prime 829*2^19536611 is prime 
Max found:
801*2^19560581 is prime 
Max found:
727*2^19585051 is prime 915*2^19586531 is prime 609*2^19618891 is prime 
Added [URL="https://primes.utm.edu/primes/page.php?id=134785"]134785[/URL] : 493*2^22387751 (673942 digits)

Max found:
657*2^19645781 is prime 921*2^19666341 is prime 611*2^19668661 is prime 
Max found:
651*2^19749181 is prime 
Added [URL="https://primes.utm.edu/primes/page.php?id=134794"]134794[/URL] : 507*2^22442371 (675586 digits)

Max found:
675*2^19827791 is prime 
Added [URL="https://primes.utm.edu/primes/page.php?id=134805"]134805[/URL] : 571*2^22487011 (676930 digits)

Max found:
781*2^19931731 is prime 
Added [URL="https://primes.utm.edu/primes/page.php?id=134812"]134812[/URL]: 655 *2^19936851 (600612 digits)

Max at the last minute on drive 14 finds:
841*2^19999511 is prime 
Max found:
377*2^22620941 is prime 
Added [URL="https://primes.utm.edu/primes/page.php?id=134823"]134823[/URL] : 489*2^22553311 (678925 digits)

Added [URL="https://primes.utm.edu/primes/page.php?id=134824"]134824[/URL] : 403*2^22543551 (678632 digits)

Max found:
351*2^23313111 is prime 
Max found:
369*2^24369491 is prime 
Max found:
373*2^24578591 is prime 
Added [URL="https://primes.utm.edu/primes/page.php?id=134954"]134954[/URL] : 493*2^22694271 (683169 digits)

Max found:
369*2^25519551 is prime 
Max found:
357*2^25681101 is prime 
Max found:
915*2^20090481 is prime 
377*2^26078561 is prime

Max found:
381*2^28012811 is prime 
Max found:
381*2^28201571 is prime 
Max found:
393*2^28287381 is prime 
Max found:
353*2^28883321 is prime 
Added 135677 : 467*2^23042981 (693666 digits)

Max found:
379*2^29114231 is prime 
Added 135692 : 553*2^23063431 (694282 digits)

Max found:
391*2^29257591 is prime 
Added [URL="https://primes.utm.edu/primes/page.php?id=135720"]135720[/URL] : 447*2^23081041 (694812 digits)

Max found:
395*2^29613701 is prime 
Max found:
369*2^29681751 is prime 
Max found:
367*2^29790331 is prime 357*2^29805401 is prime 
Max found:
811*2^20238851 is prime 
Added [URL="http://primes.utm.edu/primes/page.php?id=135743"]135743[/URL] : 495*2^23134621 (696425 digits)

Max found:
615*2^20281401 is prime 
Max found:
921*2^20302311 is prime 767*2^20303541 is prime 
The Riesel prime tables posted by Cybertronic were moved to a new thread here:
[url]https://mersenneforum.org/showthread.php?t=28526[/url] 
Max found:
777*2^20417101 is prime 
Added [URL="https://t5k.org/primes/page.php?id=135795"]135795[/URL] : 421*2^23243751 (699710 digits)

Max found:
909*2^20569371 is prime 
[url='https://t5k.org/primes/page.php?id=135805']909*2^20569371[/url] seems composite but verification status is PRP.

[QUOTE=kar_bon;626979][url='https://t5k.org/primes/page.php?id=135805']909*2^20569371[/url] seems composite but verification status is PRP.[/QUOTE]
I just now doublechecked it. LLR version 3.8.23 says otherwise: 909*2^20569371 is prime! (619203 decimal digits) Time : 1299.213 sec. Max's machines have been quite stable. He just now found another prime and I also verified that it is prime. I'll report it in the next post. The new top5000 site appears to be wrong! They need to work on their verification process. It takes many hours for the tests to start, it takes too long to run the test (over an hour for this one), and now it outputs the wrong result. Anyone else care to test this? Edit: I just now used their "let us know if anything isn't working" process to Email them about the problem. 
Max found:
813*2^20603921 is prime Doublechecked by LLR 3.8.23. 
[QUOTE=gd_barnes;626984]I just now doublechecked it. LLR version 3.8.23 says otherwise:
909*2^20569371 is prime! (619203 decimal digits) Time : 1299.213 sec. Max's machines have been quite stable. He just now found another prime and I also verified that it is prime. I'll report it in the next post. The new top5000 site appears to be wrong! They need to work on their verification process. It takes many hours for the tests to start, it takes too long to run the test (over an hour for this one), and now it outputs the wrong result. Anyone else care to test this? Edit: I just now used their "let us know if anything isn't working" process to Email them about the problem.[/QUOTE] Could be a hardware glitch on the Digital Ocean cloud ressource used by the new t5k.org. The prime is most likely good. Administrators of t5k.org are aware and have up to now prevented the deletion of the entry. Note that a proof of such c=1 candidate with LucasLehmerRiesel does not allow Gerbicz checks to catch hardware glitches. So the best way to prove primality seems to be to repeat the run on several different [I]reliable[/I] machines. /JeppeSN 
[QUOTE=JeppeSN;626986]Could be a hardware glitch on the Digital Ocean cloud ressource used by the new t5k.org. The prime is most likely good. Administrators of t5k.org are aware and have up to now prevented the deletion of the entry.
Note that a proof of such c=1 candidate with LucasLehmerRiesel does not allow Gerbicz checks to catch hardware glitches. So the best way to prove primality seems to be to repeat the run on several different [I]reliable[/I] machines. /JeppeSN[/QUOTE] Thanks for the update and info! 
[QUOTE=gd_barnes;626984]I just now doublechecked it. LLR version 3.8.23 says otherwise:
909*2^20569371 is prime! (619203 decimal digits) Time : 1299.213 sec. Anyone else care to test this?[/QUOTE] I also verified it. C:\prpnet\prpclient4>cllr64.exe v LLR Program  Version 3.8.23, using Gwnum Library Version 29.8 C:\prpnet\prpclient4>cllr64.exe t4 d q"909*2^20569371" Starting Lucas Lehmer Riesel prime test of 909*2^20569371 Using AVX FFT length 140K, Pass1=448, Pass2=320, clm=1, 4 threads V1 = 3 ; Computing U0...done. 909*2^20569371 is prime! (619203 decimal digits) Time : 1001.568 sec. Regards Odi 
I ran it using my copy of PFGW (which appears to be the same version as T5K), and I got a bunch of roundoff errors:
[code]$ ./pfgw tp q"909*2^20569371" PFGW Version 4.0.1.64BIT.20191203.x86_Dev [GWNUM 29.8] Primality testing 909*2^20569371 [N+1, BrillhartLehmerSelfridge] Running N+1 test using discriminant 5, base 1+sqrt(5) Detected in MAXERR>0.45 (round off check) in Exponentiator::Iterate Iteration: 18/2056948 ERROR: ROUND OFF 0.5>0.45 (Test aborted, try again using the a1 switch) Running N+1 test using discriminant 5, base 1+sqrt(5) Detected in MAXERR>0.45 (round off check) in Exponentiator::Iterate Iteration: 19/2056948 ERROR: ROUND OFF 0.5>0.45 (Test aborted, try again using the a2 (or possibly a0) switch) Running N+1 test using discriminant 5, base 1+sqrt(5) ^C1: 909*2^20569371 5000/2056948 mro=0.5 CtrlC detected, shutting down the program. [/code] I reran with [c]a2[/c]: [code]$ ./pfgw tp q"909*2^20569371" a2 PFGW Version 4.0.1.64BIT.20191203.x86_Dev [GWNUM 29.8] Primality testing 909*2^20569371 [N+1, BrillhartLehmerSelfridge] Running N+1 test using discriminant 5, base 1+sqrt(5) 909*2^20569371 is prime! (3940.2488s+0.0006s) [/code] 
The bad result on t5k.org is reproducible, so not a random hardware glitch.
Thought to be related to the version of GWNUM used, on hardware where the AVX512 instructions [I]are[/I] available. If someone with some version of PFGW can test on AVX512capable hardware, with [C]tp q"909*2^20569371" V[/C] where the V seems to give info about choices made by GWNUM. /JeppeSN 
[CODE]$ ./pfgw64 tp q"909*2^20569371" V
PFGW Version 4.0.4.64BIT.20221214.x86_Dev [GWNUM 30.11] Primality testing 909*2^20569371 [N+1, BrillhartLehmerSelfridge] Running N+1 test using discriminant 5, base 1+sqrt(5) Special modular reduction using AVX512 FFT length 144K, Pass1=192, Pass2=768, clm=1 on 909*2^20569371 909*2^20569371 is prime! (1746.6204s+0.0004s)[/CODE] 
I just got an Email from Reginald, the new top5000 server admin, that the problem has been fixed.
The problem was related to having an older version of PFGW combined with AVX512 hardware. They rebuilt PFGW from the latest source, installed it on the server, and confirmed the prime. Thank you to the new top5000 admins for taking care of this and to everyone else for verifying the prime! :smile: 
[QUOTE=gd_barnes;626984]I just now doublechecked it. LLR version 3.8.23 says otherwise:
909*2^20569371 is prime! (619203 decimal digits) Time : 1299.213 sec. Max's machines have been quite stable. He just now found another prime and I also verified that it is prime. I'll report it in the next post. The new top5000 site appears to be wrong! They need to work on their verification process. It takes many hours for the tests to start, it takes too long to run the test (over an hour for this one), and now it outputs the wrong result. Anyone else care to test this? Edit: I just now used their "let us know if anything isn't working" process to Email them about the problem.[/QUOTE] Ah, yes  I noticed the same issue last night. The top5000 site sent me an automatic email informing me of the verification failure. I retested the candidate myself last night twice using different programs, the first time with the very latest LLR2 v1.3.3 (gwnum 30.11), and the second as an N+1 test with an older PFGW 3.7.10 (gwnum 28.7), similar to what the top5000 site tried to run. Both confirmed primality without issue  although like others here, I did get several roundoff errors during the PFGW test (which PFGW was able to detect and selfheal by going to a more cautious FFT). I wouldn't be surprised if the reason the problem only showed up just now on this candidate is because it's most sensitive near an FFT boundary (where selfcorrecting roundoff errors like this are common  but might not be selfcorrecting if there's an underlying hardware/software issue). I was going to email them myself about it today, but was busy for much of the day and by the time I checked in the evening, saw that the top5000 site was already actively retrying it. (The first retry failed again, but I saw another one was in progress, which ultimately turned out prime.) Now I see that's because Gary emailed them  thanks! :smile: Glad to see the root cause was found and resolved (per Gary's note just above)  and that everyone here is so on top of this! I was wondering if it was something like an AVX512 issue, as that's the only sort of issue I could imagine manifesting like this in a cloudcomputing environment (where the hardware is invariably servergrade with ECC RAM, which prevents most "random" bitflip errors). 
Max found:
983*2^20640201 is prime 
Added [URL="https://t5k.org/primes/page.php?id=135816"]135816[/URL] : 413*2^23270481 (700514 digits)

Added [URL="http://t5k.org/primes/page.php?id=135824"]135824[/URL] : 831*2^20706221 (623323 digits)

Max found:
867*2^20721421 is prime 
Max found:
825*2^20758001 is prime 
Max found:
777*2^20768411 is prime 
Max found:
615*2^20893291 is prime 
Added [URL="https://t5k.org/primes/page.php?id=135860"]135860[/URL] : 535*2^23389711 (704104 digits)

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