Found with PFGW Version 3.6.0

3351^6718-6718^3351 is 2-PRP! (26.5709s+0.0074s)
3351^6718-6718^3351 is 3-PRP! (23.8347s+0.0047s)
3351^6718-6718^3351 is 5-PRP! (23.8245s+0.0040s)
3351^6718-6718^3351 is 7-PRP! (23.5941s+0.0121s)
3351^6718-6718^3351 is 11-PRP! (23.5988s+0.0040s)

Primality testing 3351^6718-6718^3351 [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 0.07% and helper 0.01% (0.22% proof)
3351^6718-6718^3351 is Fermat and Lucas PRP! (113.0245s+0.0043s)

To be completed...