A377676 a(n) is the number of divisors of n^n - n.

2, 8, 18, 40, 24, 120, 48, 336, 80, 192, 72, 1920, 48, 288, 23040, 1728, 36, 10240, 72, 7680, 432, 240, 384, 32256, 640, 49152, 2016, 3840, 96, 193536, 1152, 22528, 1152, 4608, 1327104, 1638400, 96, 7680, 9216, 4128768, 384, 294912, 72, 23040, 30720, 576

Offset

2,1

Links

Amiram Eldar, Table of n, a(n) for n = 2..115

Formula

a(n) = A000005(A061190(n)).

Mathematica

a[n_] := DivisorSigma[0, n^n - n]; Array[a, 45, 2] (* Amiram Eldar, Nov 04 2024 *)

Prog

(PARI) a(n) = numdiv(n^n-n);

Crossrefs

Cf. A000005, A061190, A334167, A372229, A372599, A377672, A377675, A377677, A377678.

Sequence in context: A252592 A188577 A064705 * A220909 A376192 A058858

Adjacent sequences: A377673 A377674 A377675 * A377677 A377678 A377679

Keyword

nonn

Author

Sean A. Irvine, Nov 03 2024

Status

approved