A324941 Largest prime factor of 17^n + 1.

2, 3, 29, 13, 41761, 101, 83233, 22796593, 184417, 5653, 63541, 87415373, 72337, 2001793, 100688449, 238212511, 52548582913, 45957792327018709121, 382069, 20352763, 1186844128302568601, 88109799136087, 6901823633, 1109309383381084655697725873, 48661191868691111041

Offset: 0

Author

Vincenzo Librandi, Apr 05 2019

Keywords

• nonn

Links

• Max Alekseyev, Table of n, a(n) for n = 0..211

Crossrefs

Cf. A006530, A224384.

Cf. A002587, A074476, A274903, A074478, A274904, A227575, A274905, A002592, A003021, A062308, A002590.

Programs

Magma

[Maximum(PrimeDivisors(17^n + 1)): n in [0..40]];

Mathematica

Table[FactorInteger[17^n + 1] [[-1,1]], {n, 0, 30}]

PARI

a(n) = vecmax(factor(17^n+1)[, 1]); \\ Jinyuan Wang, Apr 05 2019

Formula

a(n) = A006530(A224384(n)).