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Message boards : General discussion : Cunningham Chain sieving

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John
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Message 70782 - Posted: 10 Nov 2013 | 3:31:59 UTC

I just started looking at Cunningham Chain records on http://users.cybercity.dk/~dsl522332/math/Cunningham_Chain_records.htm , and was wondering on file preparation for testing for a certain length. Lets say I was looking for a "2nd kind" chain of length=5... could I sieve, say, 100 consecutive n-values for 1<k<1e9 for k*2^n+1 (odds only of course), then merge all the files and sort by k somehow so I could LLR test only those k values that have 5 or more consecutive n's without having to go through the file myself (taking hours, I'm sure)? If so, how would you suggest doing so?

KEPProject donor
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Message 70789 - Posted: 10 Nov 2013 | 12:38:12 UTC - in response to Message 70782.

As I understand what you're writing, then you are looking for cunningham chains of 2nd kind, with a chain length of 5.

If you go to this website http://primes.utm.edu/bios/page.php?id=105 and downloads NewPGen and then opens NewPGen and under "Type" you choose "CC 2nd kind" and changes the length from 3 to 5. You can however only sieve 1 n at a time, but the outputfile that NewPGen will create will only contain the candidates that has a length of 5, all other candidates will have been removed, since they doesn't meet your requirements, since one or more candidates in the chain has a factor.

The rest should be selfexplanatory, but if you have further questions, either ask them here or send me a PM and I'll gladly help you :)

Regards

KEP

Message boards : General discussion : Cunningham Chain sieving

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