Primality testing 647^19118-19118^647 [N-1/N+1, Brillhart-Lehmer-Selfridge]
Running N-1 test using base 3
Running N-1 test using base 5
Running N+1 test using discriminant 19, base 3+sqrt(19)
Calling N-1 BLS with factored part 0.00% and helper 0.00% (0.01% proof)
647^19118-19118^647 is Fermat and Lucas PRP! (102.4741s+0.0009s)

Sieved with xyyxsieve

To be completed...