Found with PFGW Version 3.7.5

631^7884-7884^631 is 2-PRP! (17.4662s+0.0010s)
631^7884-7884^631 is 3-PRP! (18.6797s+0.0012s)
631^7884-7884^631 is 5-PRP! (18.3464s+0.0007s)
631^7884-7884^631 is 7-PRP! (17.6910s+0.0008s)
631^7884-7884^631 is 11-PRP! (17.7457s+0.0007s)

Primality testing 631^7884-7884^631 [N-1/N+1, Brillhart-Lehmer-Selfridge]
Running N-1 test using base 5
Running N+1 test using discriminant 11, base 1+sqrt(11)
Calling N+1 BLS with factored part 0.11% and helper 0.04% (0.36% proof)
631^7884-7884^631 is Fermat and Lucas PRP! (92.0632s+0.3701s)

To be completed...