Found with PFGW Version 3.7.5

3471^7642-7642^3471 is 2-PRP! (30.9115s+0.0041s)
3471^7642-7642^3471 is 3-PRP! (31.5504s+0.0042s)
3471^7642-7642^3471 is 5-PRP! (29.1024s+0.0043s)
3471^7642-7642^3471 is 7-PRP! (31.8920s+0.0046s)
3471^7642-7642^3471 is 11-PRP! (31.3096s+0.0045s)

Primality testing 3471^7642-7642^3471 [N-1/N+1, Brillhart-Lehmer-Selfridge]
Running N-1 test using base 3
Running N+1 test using discriminant 11, base 1+sqrt(11)
Calling N-1 BLS with factored part 0.02% and helper 0.01% (0.08% proof)
3471^7642-7642^3471 is Fermat and Lucas PRP! (157.9182s+0.0048s)

To be completed...