A366670 Smallest prime dividing 6^n + 1.

2, 7, 37, 7, 1297, 7, 13, 7, 17, 7, 37, 7, 1297, 7, 37, 7, 353, 7, 13, 7, 41, 7, 37, 7, 17, 7, 37, 7, 281, 7, 13, 7, 2753, 7, 37, 7, 577, 7, 37, 7, 17, 7, 13, 7, 89, 7, 37, 7, 193, 7, 37, 7, 1297, 7, 13, 7, 17, 7, 37, 7, 41, 7, 37, 7, 4926056449, 7, 13, 7, 137

Offset: 0

Author

Sean A. Irvine, Oct 15 2023

Keywords

• nonn

Links

• Max Alekseyev, Table of n, a(n) for n = 0..4095

Crossrefs

Cf. A020639, A062394, A274904, A366630.

Cf. A002586, A366609, A366671, A038371, A366719.

Programs

Mathematica

Table[FactorInteger[6^n + 1][[1,1]], {n, 0, 68}] (* Paul F. Marrero Romero, Oct 17 2023 *)

Formula

a(n) = A020639(A062394(n)). - Paul F. Marrero Romero, Oct 17 2023