%I #22 May 05 2022 00:45:24

%S 2,4,8,12,16,16,96,128,48,16,256,48,32,128,128,40,512,12,2048,768,256,

%T 64,6144,4096,768,512,4096,768,24576,16,6144,768,8192,1024,262144,

%U 1152,256,1024,49152,256,65536,64,24576,196608,384,32,393216,327680,12288,24576

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

%C 25 values of the first 40 are powers of 2.

%H Max Alekseyev, <a href="/A334167/b334167.txt">Table of n, a(n) for n = 2..138</a>

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

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

%o (PARI) a(n) = numdiv(n^n-1); \\ _Michel Marcus_, Apr 17 2020

%Y Cf. A000005, A048861, A006486, A116895, A344859.

%K nonn

%O 2,1

%A _Todor Szimeonov_, Apr 17 2020

%E More terms from _Giovanni Resta_, Apr 17 2020