A366689 Sum of the divisors of 11^n+1.

3, 28, 186, 3458, 21966, 375816, 2911272, 45470096, 340452396, 6278429920, 39543942612, 706019328000, 4708961513592, 82162955169792, 599236951715280, 11195197038864384, 68925937595777100, 1179397832668228992, 9136813499663186064, 144079834776308121600

Offset: 0

Author

Sean A. Irvine, Oct 16 2023

Keywords

• nonn

Examples

			a(4)=21966 because 11^4+1 has divisors {1, 2, 7321, 14642}.
		

Links

• Max Alekseyev, Table of n, a(n) for n = 0..325

Crossrefs

Cf. A034524, A000203, A366666, A366684, A366686, A366687, A366688, A366690, A366715.

Programs

Maple

a:=n->numtheory[sigma](11^n+1):
seq(a(n), n=0..100);

Mathematica

DivisorSigma[1,11^Range[0,20]+1] (* Harvey P. Dale, Jun 22 2025 *)

Formula

a(n) = sigma(11^n+1) = A000203(A034524(n)).