View Single Post
Old 2019-06-26, 13:37   #13
GP2's Avatar
Sep 2003

A1916 Posts

Originally Posted by mathwiz View Post
What program was used to find factors of W(W(61)) onward?
Originally Posted by GP2 View Post
All Wagstaff factors are 2*k*p + 1 for some k, just like with Mersenne. And k is small enough for those factors that you could quickly find them even with a dumb Python script.
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.

Last fiddled with by GP2 on 2019-06-26 at 14:14
GP2 is offline   Reply With Quote