Largest prime factor of 5^n - 3^n.
2, 2, 7, 17, 131, 19, 883, 353, 181, 421, 363067, 37, 609554401, 10039, 3541, 198593, 162507523, 12979, 9536162033329, 2861, 18306583, 363067, 5960417405949649, 346561, 103408180634401, 609554401, 3853528045489, 6195029, 4522957755638831, 15391
1
T. D. Noe, Plot of 100 terms
T. D. Noe, Table of 100 terms
Eric W. Weisstein, MathWorld: Greatest Prime Factor
(Mma) Table[FactorInteger[5^n - 3^n][[-1, 1]], {n, 40}]
nonn
T. D. Noe, Jun 08 2015