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
MATHEMATICA
a[n_] := DivisorSigma[0, n^n - 1]; a /@ Range[2, 45] (* Giovanni Resta, Apr 17 2020 *)
PROG
(PARI) a(n) = numdiv(n^n-1); \\ Michel Marcus, Apr 17 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
Todor Szimeonov, Apr 17 2020
EXTENSIONS
More terms from Giovanni Resta, Apr 17 2020
STATUS
approved