A366629 Sum of the divisors of 6^n+1.

3, 8, 38, 256, 1298, 9792, 52136, 338580, 1778436, 11889152, 62367272, 414625216, 2178461956, 15224775552, 80673299432, 611106029568, 2830769440776, 19344856702976, 115255634181184, 696800841097536, 3748220725527432, 27388329197137920, 135183433256806480

Offset: 0

Author

Sean A. Irvine, Oct 14 2023

Keywords

• nonn

Examples

			a(3)=256 because 6^3+1 has divisors {1, 7, 31, 217}.
		

Links

• Max Alekseyev, Table of n, a(n) for n = 0..430

Crossrefs

Cf. A062394, A000203, A057938, A366622, A366617, A366627, A366628, A366630, A366670.

Cf. A069061, A366578, A366607, A366638, A366657, A366666, A366668, A366689, A366715.

Programs

Maple

a:=n->numtheory[sigma](6^n+1):
seq(a(n), n=0..100);

Mathematica

DivisorSigma[1, 6^Range[0, 30] + 1] (* Paolo Xausa, Jul 03 2024 *)

Formula

a(n) = sigma(6^n+1) = A000203(A062394(n)).