Largest prime factor of 8^n - 5^n.
3, 13, 43, 89, 241, 43, 9479, 4721, 3079, 251, 213533, 3121, 13001, 167329, 296551, 1009873, 3875812253, 11251, 48032038196509249, 67261, 671791, 28892183, 4232248607231, 5113, 1274453794816087601, 129533, 3471121, 1706373509, 727750509785297587213, 296551
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[8^n - 5^n][[-1, 1]], {n, 40}]
nonn
T. D. Noe, Jun 08 2015