Primality testing 41^11991-40 [N-1/N+1, Brillhart-Lehmer-Selfridge]
Running N-1 test using base 13
Running N-1 test using base 17
Running N-1 test using base 31
Running N+1 test using discriminant 47, base 4+sqrt(47)
Calling N-1 BLS with factored part 0.33% and helper 0.06% (1.06% proof)
41^11991-40 is Fermat and Lucas PRP! (872.734000 seconds)

To be completed...