Found with PFGW Version 3.6.0

2421^4312-4312^2421 is 2-PRP! (9.8657s+0.0022s)
2421^4312-4312^2421 is 3-PRP! (9.8812s+0.0033s)
2421^4312-4312^2421 is 5-PRP! (10.2708s+0.0022s)
2421^4312-4312^2421 is 7-PRP! (11.1598s+0.0020s)
2421^4312-4312^2421 is 11-PRP! (9.9125s+0.0019s)

Primality testing 2421^4312-4312^2421 [N-1/N+1, Brillhart-Lehmer-Selfridge]
Running N-1 test using base 3
Running N+1 test using discriminant 13, base 1+sqrt(13)
Calling N+1 BLS with factored part 0.09% and helper 0.07% (0.35% proof)
2421^4312-4312^2421 is Fermat and Lucas PRP! (46.7216s+0.0023s)

To be completed...