Primality testing 28724^33353-33353^28724 [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 base 7
Running N+1 test using discriminant 17, base 1+sqrt(17)
Calling N-1 BLS with factored part 0.01% and helper 0.00% (0.02% proof)
28724^33353-33353^28724 is Fermat and Lucas PRP! (1360.7592s+0.0032s)

Sieved with xyyxsieve

To be completed...