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Old 2019-06-26, 17:07   #14
Dylan14's Avatar
Mar 2017

24F16 Posts

Originally Posted by GP2 View Post
The Double Mersenne Prime Search uses a program called mmff.exe, which is derived from mfaktc.exe

As you mentioned, with mfaktc.exe it suffices to set the -DWAGSTAFF flag to make it find Wagstaff factors instead of Mersenne factors. So maybe that will work with mmff.exe as well, and it might be possible to find a large-ish factor for W(W(43)).

Edit: from looking at the source code, it's not that simple.
Instead of trying to modify mmff to handle double Wagstaff numbers, it might be easier to modify dmdsieve from the mtsieve suite. In this case the appropriate header to pass to pfgw would be

ABCD 2*$a*((2^p+1)/3)+1
where $a is a k value not sieved out and p is an exponent of a Wagstaff (probable) prime.
(Of course, more work is needed to get the sieve to work.)
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