Thread: Octoproths
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Old 2006-01-13, 13:46   #241
Greenbank's Avatar
Jul 2005

1100000102 Posts

OK, thanks to Robert Gerbicz's PARI program (which I've slightly adapted) I now have a nice script to validate the primality of the numbers we find.

Of course you need PARI installed and it isn't much different from Robert's original version.

The output looks like this:-

562223326335,235 PPPPCCCC
722744559915,235 PPPPCPCC
926010118305,235 PPPPCPCC
2441346583515,235 PPPPCCCC
305676859408095,338 PPPPPPPP

The first 4 were the ones found with axn1's Pascal program which let a few more pseudo-primes through than octo.exe. You'll notice they all passed the first 4 tests but failed 3 or 4 of the last 4.

The last one is Kosmaj's current record holding OP for n=338! 8 P's = OctoProth! (117 digits for the largest!)

Mean time I put my Quad G5 to good use and I've completed the search ranges for all n <=48 (and 49,50 and 51 are in progress).

I'll run all of the results_octo.txt files through the prime validation script and post the results.

I'll also make the entire lists of OPs for n<=48 (and soon to be n<=51) available for download (although it will be a reasonably big file).

Last fiddled with by Greenbank on 2006-01-13 at 14:21
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