Found with PFGW Version 3.8.0

11966^12553-12553^11966 is 2-PRP! (47.6342s+0.0073s)
11966^12553-12553^11966 is 3-PRP! (47.5844s+0.0083s)
11966^12553-12553^11966 is 5-PRP! (47.4020s+0.0150s)
11966^12553-12553^11966 is 7-PRP! (48.4344s+0.0077s)
11966^12553-12553^11966 is 11-PRP! (48.8405s+0.0080s)

Primality testing 11966^12553-12553^11966 [N-1/N+1, Brillhart-Lehmer-Selfridge]
Running N-1 test using base 3
Running N+1 test using discriminant 11, base 2+sqrt(11)
Calling N-1 BLS with factored part 0.02% and helper 0.01% (0.06% proof)
11966^12553-12553^11966 is Fermat and Lucas PRP! (272.2092s+0.0081s)

To be completed...