A334167 - OEIS

A334167

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

2, 4, 8, 12, 16, 16, 96, 128, 48, 16, 256, 48, 32, 128, 128, 40, 512, 12, 2048, 768, 256, 64, 6144, 4096, 768, 512, 4096, 768, 24576, 16, 6144, 768, 8192, 1024, 262144, 1152, 256, 1024, 49152, 256, 65536, 64, 24576, 196608, 384, 32, 393216, 327680, 12288, 24576

(list; graph; refs; listen; history; text; internal format)

OFFSET

2,1

COMMENTS

25 values of the first 40 are powers of 2.

LINKS

Max Alekseyev, Table of n, a(n) for n = 2..138

FORMULA

a(n) = A000005(A048861(n)).

MATHEMATICA

a[n_] := DivisorSigma[0, n^n - 1]; a /@ Range[2, 45] (* Giovanni Resta, Apr 17 2020 *)

PROG