Primality testing 26990^27263-27263^26990 [N-1/N+1, Brillhart-Lehmer-Selfridge]
Running N-1 test using base 3
Running N-1 test using base 11
Running N+1 test using discriminant 19, base 1+sqrt(19)
Calling N-1 BLS with factored part 0.01% and helper 0.01% (0.03% proof)
26990^27263-27263^26990 is Fermat and Lucas PRP! (619.3923s+0.0024s)

Sieved with xyyxsieve

To be completed...