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Old 2020-07-21, 03:40   #24
gd_barnes's Avatar
May 2007
Kansas; USA

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Originally Posted by sweety439 View Post
The divisor of k*b^n+-1 (+ for Sierp, - for Riesel) is always gcd(k+-1,b-1) (+ for Sierp, - for Riesel) (see post, since gcd(k+-1,b-1) is the trivial factor of k*b^n+-1, it is simply to take out this factor, thus, the divisor of R43, k=13 is 6, not 2 (gcd(13-1,43-1) = 6), and the formula of R43, k=13 is (13*43^n-1)/6, not (13*43^n-1)/2
Of course you are correct. I was only giving a simplified example. Even though the divisor here is 6 we still have the same problem with srsieve or srsieve2 giving an immediate error when all candidates are divisible by 2.

We simply need this error check removed from srsieve and/or srsieve2.

Last fiddled with by gd_barnes on 2020-07-21 at 03:41
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