21-digit factor of general number by WE, in seconds...
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bearnol
Aug 29, 2008, 11:38:22 AM8/29/08
to Mersenneplustwo
...shows the WE algorithm can work spectacularly well, at least
_sometimes_!
A while ago, while experimenting with the WE algorithm (actually
running as part of superfac9), I came across this particular
combination of primes into a semiprime, after a dozen or so attempts,
which yields an 11-digit factor by WE almost instantly:
f(10^10+19)*(2^521-1)
Just now I thought I'd try and extend the experiment, and once again,
after about a dozen attempts, the following semiprime yields a 21-
digit factor by WE almost instantly:
f(2^1279-1)*(10^20+151)
This is, I believe, the largest factor I've found by the WE algorithm
to date, from a generic number. Good news indeed!
J
_sometimes_!
A while ago, while experimenting with the WE algorithm (actually
running as part of superfac9), I came across this particular
combination of primes into a semiprime, after a dozen or so attempts,
which yields an 11-digit factor by WE almost instantly:
f(10^10+19)*(2^521-1)
Just now I thought I'd try and extend the experiment, and once again,
after about a dozen attempts, the following semiprime yields a 21-
digit factor by WE almost instantly:
f(2^1279-1)*(10^20+151)
This is, I believe, the largest factor I've found by the WE algorithm
to date, from a generic number. Good news indeed!
J
bearnol
Sep 1, 2008, 10:44:34 AM9/1/08
to Mersenneplustwo
I think I've found out how to construct these...
here's another that finds a 36-digit factor instantly:
f(2^102*2203+1)*(2^2203-1)
J
here's another that finds a 36-digit factor instantly:
f(2^102*2203+1)*(2^2203-1)
J
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