Primality testing 1406^21657-21657^1406 [N-1/N+1, Brillhart-Lehmer-Selfridge]
Running N-1 test using base 5
Running N+1 test using discriminant 23, base 1+sqrt(23)
Calling N+1 BLS with factored part 0.01% and helper 0.00% (0.04% proof)
1406^21657-21657^1406 is Fermat and Lucas PRP! (215.3681s+0.0014s)

Sieved with xyyxsieve

To be completed...