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paulunderwood · 2020-07-25, 15:49

Consider x^2-2*x-1=0. This has solutions x= 1 +- sqrt(2). But 2^((W-1)/2) == -1 mod W where W=(2^p+1)/3 because kronecker(2,W) == -1. I propose the test:

Mod(Mod(1,W)*x,x^2-2*x-1)^(W+1)==-1 for Wagstaffs.

2020-07-25, 15:49	#5
paulunderwood Sep 2002 Database er0rr 2²·1,063 Posts	Consider x^2-2x-1=0. This has solutions x= 1 +- sqrt(2). But 2^((W-1)/2) == -1 mod W where W=(2^p+1)/3 because kronecker(2,W) == -1. I propose the test: Mod(Mod(1,W)x,x^2-2x-1)^(W+1)==-1 for Wagstaffs. Last fiddled with by paulunderwood on 2020-07-25 at 15:54*