Found with PFGW Version 3.6.0

4209^4828-4828^4209 is 2-PRP! (13.3827s+0.0034s)
4209^4828-4828^4209 is 3-PRP! (13.3281s+0.0051s)
4209^4828-4828^4209 is 5-PRP! (13.3491s+0.0045s)
4209^4828-4828^4209 is 7-PRP! (13.2973s+0.0025s)
4209^4828-4828^4209 is 11-PRP! (13.2592s+0.0024s)

Primality testing 4209^4828-4828^4209 [N-1/N+1, Brillhart-Lehmer-Selfridge]
Running N-1 test using base 3
Running N+1 test using discriminant 7, base 1+sqrt(7)
Calling N-1 BLS with factored part 0.03% and helper 0.02% (0.10% proof)
4209^4828-4828^4209 is Fermat and Lucas PRP! (63.5812s+0.0021s)

To be completed...