Found with PFGW Version 3.7.5

6690^7669-7669^6690 is 2-PRP! (31.4358s+0.0030s)
6690^7669-7669^6690 is 3-PRP! (32.3425s+0.0031s)
6690^7669-7669^6690 is 5-PRP! (27.7941s+0.0027s)
6690^7669-7669^6690 is 7-PRP! (25.7523s+0.0028s)
6690^7669-7669^6690 is 11-PRP! (29.6042s+0.0029s)

Primality testing 6690^7669-7669^6690 [N-1/N+1, Brillhart-Lehmer-Selfridge]
Running N-1 test using base 7
Running N+1 test using discriminant 13, base 1+sqrt(13)
Calling N+1 BLS with factored part 0.04% and helper 0.02% (0.14% proof)
6690^7669-7669^6690 is Fermat and Lucas PRP! (177.1178s+0.0056s)

To be completed...