1st PRP for 2^n-424421.

Sieved to P=200G.

Primality testing 2^85842-424421 [N-1/N+1, Brillhart-Lehmer-Selfridge]
Running N-1 test using base 7
Running N+1 test using discriminant 17, base 1+sqrt(17)
Calling N+1 BLS with factored part 0.02% and helper 0.00% (0.07% proof)
2^85842-424421 is Fermat and Lucas PRP! (364.8494s+0.0047s)

To be completed...