1st PRP for 2^n-254143.

Sieved to P=200G.

Primality testing 2^41257-254143 [N-1/N+1, Brillhart-Lehmer-Selfridge]
Running N-1 test using base 73
Running N-1 test using base 97
Running N+1 test using discriminant 103, base 2+sqrt(103)
Calling N-1 BLS with factored part 0.05% and helper 0.05% (0.21% proof)
2^41257-254143 is Fermat and Lucas PRP! (97.4251s+0.0064s)

To be completed...