Found with PFGW Version 3.6.0

783^4870-4870^783 is 2-PRP! (9.6620s+0.0032s)
783^4870-4870^783 is 3-PRP! (9.6416s+0.0025s)
783^4870-4870^783 is 5-PRP! (9.5650s+0.0017s)
783^4870-4870^783 is 7-PRP! (9.5127s+0.0017s)
783^4870-4870^783 is 11-PRP! (9.5449s+0.0018s)

Primality testing 783^4870-4870^783 [N-1/N+1, Brillhart-Lehmer-Selfridge]
Running N-1 test using base 3
Running N+1 test using discriminant 11, base 7+sqrt(11)
Calling N+1 BLS with factored part 0.03% and helper 0.03% (0.11% proof)
783^4870-4870^783 is Fermat and Lucas PRP! (45.0058s+0.0021s)

To be completed...