OFFSET
1,2
LINKS
Indranil Ghosh, Table of n, a(n) for n = 1..25000
EXAMPLE
For n=10, a(10) = floor(sigma(sigma(10))/10) = floor(sigma(18)/10) = floor(39/10) = 3.
MATHEMATICA
Table[Floor[Nest[DivisorSigma[1, #] &, n, 2]/n], {n, 120}] (* Michael De Vlieger, Mar 02 2017 *)
PROG
(PARI) a(n) = sigma(sigma(n))\n; \\ Michel Marcus, Oct 07 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Oct 25 2004
STATUS
approved