A366819 a(n) is the sum of the divisors of n^n-1.

4, 42, 432, 6048, 67584, 1704240, 38054016, 967814400, 16203253248, 513593801496, 15743437516800, 720045832568832, 19146847615988736, 835966563470742528, 31421980989189888768, 1602925310146310674200, 52064744760120508416000, 4286575920597346109768658

Offset

2,1

Links

Amiram Eldar, Table of n, a(n) for n = 2..138

Formula

a(n) = A000203(A048861(n)).

Mathematica

Array[DivisorSigma[1, #^# - 1] &, 18, 2] (* Michael De Vlieger, Oct 24 2023 *)

Prog

(PARI) a(n) = sigma(n^n-1);

Crossrefs

Cf. A000203, A048861, A309941, A344870, A334167, A062727, A366820.

Sequence in context: A213103 A085954 A046719 * A335776 A092800 A370282

Adjacent sequences: A366816 A366817 A366818 * A366820 A366821 A366822

Keyword

nonn

Author

Sean A. Irvine, Oct 24 2023

Status

approved