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Old 2007-06-24, 07:38   #3
gd_barnes's Avatar
May 2007
Kansas; USA

2·5·1,013 Posts

Thanks, Citrix, for adding to my list. I think it's great to have a comprehensive list of all primes and twin primes of certain forms up to certain limits of k and n before going after the really big primes.

For my list, I unofficially tested k=1 to 600 (i.e. ran no programs) up to the lower limit of where primes were tested to on the Riesel and Proth search sites by matching up the k's and n's. This has usually been up to at least n=200K because both Riesel and Proth primes have been mostly tested at least that high for all k's < 600. So I think doing any further twin testing for k < 600 would not be worthwile because even trying to find one twin above n=200K would take months and possibly years without a large coordinated effort.

I have 3 decent-speed machines working on other prime efforts right now that I want to continue on for several weeks yet and a very slow older machine that I use for sieving while the others are prime testing. I think I'll do 3 things here to continue this process:
1. Specify exactly how far each of the k's on my list have been tested. Yours are specifically tested to n=250, but I can't say for sure how high of an n each k is tested on mine without looking more closely at the various sites.
2. Add your primes to my list.
3. Once my slow-speed machine (333 mhz) is done with it's current sieve in about 2 days, I'll use it to test your k's to higher n's for twins. As slow as it is, I'll either limit the n's to 1000 or limit the k's to 2000 and allow the n's to go up to 10000 or so. Obviously these are very rough estimates only.

Also to be determined for my list...what gaps exist in the primes for the k's listed on the RPS, i.e. 15k, site, the Primesearch site, and the Proth search site. It's not immediately obvious where gaps exists. One gap that I know of for sure on Riesel primes is for k=289 from n=300K to n=501991. I checked around on another area in this forum and no one could say for sure that the range had been tested so I reserved it. I currently have my highest-speed dual-core machine working on the entire range. Any other Riesel prime that I find in that range will also be tested for a twin or checked for the same n on the Proth search site.

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