Largest prime factor of 3^n - 2^n.
1, 5, 19, 13, 211, 19, 71, 97, 1009, 211, 331, 61, 29927, 463, 3571, 401, 129009091, 1009, 745181, 4621, 6217, 35839, 2002867877, 5521, 39756701, 29927, 397760329, 369181, 68629840493971, 3571, 617671248800299, 14177, 24939553, 129009091, 18906721, 1009
1
We include the first term even though it is not prime. The n that produce prime 3^n - 2^n are in A057468.
T. D. Noe, Plot of 100 terms
T. D. Noe, Table of 100 terms
Eric W. Weisstein, MathWorld: Greatest Prime Factor
(Mma) Table[FactorInteger[3^n - 2^n][[-1, 1]], {n, 40}]
nonn
T. D. Noe, Jun 08 2015