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-   -   Carol / Kynea Primes (https://www.mersenneforum.org/showthread.php?t=21251)

 lalera 2016-04-29 00:19

hi,
here are the results for carol / kynea
b=74, n=20000 to 40000
(74^39227-1)^2-2
continuing

 Batalov 2016-05-05 06:23

After a bit of a side trip with xy-yx's, continued with the CK's search and found a slightly larger one: [URL="http://factordb.com/index.php?id=1100000000838084937"](20^72820-1)^2-2[/URL]
(current limits are 10: [95000], 20: [74000], 30: [65000], 40: [60000])

 lalera 2016-05-05 12:35

hi,
here are the results for carol / kynea
b=6, n=50000 to 100000
(6^50800+1)^2-2
continuing

 lalera 2016-05-05 14:06

hi,
here are the results for
b=70, n=1000 to 10000
no prime
b=72, n=1000 to 10000
(72^1920+1)^2-2
(72^6831+1)^2-2

 wombatman 2016-05-05 15:53

For b = 26:

Tested through n=14,084 - 34,000 (would be higher, but I oversieved a bit)

Primes:
[CODE](26^19545+1)^2-2[/CODE]

Continuing on to n=100,000

 rogue 2016-05-05 16:17

[QUOTE=wombatman;433150]For b = 26:

Tested through n=14,084 - 34,000 (would be higher, but I oversieved a bit)

Primes:
[CODE](26^19545+1)^2-2[/CODE]

Continuing on to n=100,000[/QUOTE]

Thanks for the update. What did you sieve to? How many tests do you have to do in that range?

 wombatman 2016-05-05 16:31

Sieve is to P=~3.22e12. I stopped when I saw that the seconds per factor were over 500, and I figured that the PRP tests would be faster than that.

Assuming the range you're referring to is from n=34,000 to n=100,000, there are approximately 11,000 tests or so to go.

 rogue 2016-05-05 17:04

[QUOTE=wombatman;433154]Sieve is to P=~3.22e12. I stopped when I saw that the seconds per factor were over 500, and I figured that the PRP tests would be faster than that.

Assuming the range you're referring to is from n=34,000 to n=100,000, there are approximately 11,000 tests or so to go.[/QUOTE]

Then you might have not sieved deeply enough. You probably want the removal rate to be between 1000 and 1500 seconds per factor, depending upon the hardware you are running. Also, are you using the latest cksieve? It is about 50% faster than the earlier ones.

 wombatman 2016-05-05 20:44

I am, yes. Current PRP tests are taking ~250 seconds per test, compared to finding factors at 500+ seconds per factor. I know that at some point it will make sense to sieve more, but I was thinking that would occur when the PRP test was in the neighborhood of the sec/factor time.

Would you recommend sieving more now?

 rogue 2016-05-05 20:57

[QUOTE=wombatman;433174]I am, yes. Current PRP tests are taking ~250 seconds per test, compared to finding factors at 500+ seconds per factor. I know that at some point it will make sense to sieve more, but I was thinking that would occur when the PRP test was in the neighborhood of the sec/factor time.

Would you recommend sieving more now?[/QUOTE]

No. You can. See what the speed is around n=50,000. You might consider doing more sieving when you get there.

 wombatman 2016-05-05 21:20

Will do. Thanks.

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