S000654


Largest prime factor of 5^n - 4^n.

1, 3, 61, 41, 191, 61, 2129, 881, 1459, 461, 7019, 61, 14602459, 10501, 7411, 26833, 248779, 3907, 22639679, 263761, 594511, 256147, 6031199, 4057, 3818201, 14602459, 94425589, 120569, 1482830563601, 362581, 108897707976754259, 32677121, 42730786509181

1

S000654

We include the first term even though it is not prime. The n that produce prime 5^n - 4^n are in A059802.

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 - 4^n][[-1, 1]], {n, 40}]

Cf. A059802, S000650-S000668.

nonn

T. D. Noe, Jun 08 2015

© Tony D Noe 2014-2015