Largest prime factor of 6^n - 5^n.
1, 11, 13, 61, 4651, 31, 6959, 113, 127, 4651, 313968931, 1021, 11839990891, 6959, 1038811, 2070241, 651169, 35281, 3090503945981, 6361, 44647, 313968931, 777809294098524691, 1249, 6048648636003601, 11839990891, 70138897327, 1384716061
1
We include the first term even though it is not prime. The n that produce prime 6^n - 5^n are in A062572.
T. D. Noe, Plot of 100 terms
T. D. Noe, Table of 100 terms
Eric W. Weisstein, MathWorld: Greatest Prime Factor
(Mma) Table[FactorInteger[6^n - 5^n][[-1, 1]], {n, 40}]
nonn
T. D. Noe, Jun 08 2015