OFFSET
1,2
LINKS
MAPLE
with(numtheory); f:=n->sigma(sigma(sigma(sigma(sigma(n))))); [seq(f(n), n=1..100)];
MATHEMATICA
Table[Nest[DivisorSigma[1, #]&, n, 5], {n, 50}] (* Harvey P. Dale, Apr 19 2013 *)
PROG
(PARI) A162964(n) = sigma(sigma(sigma(sigma(sigma(n))))); \\ Antti Karttunen, Nov 18 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Jul 19 2009
EXTENSIONS
More terms from N. J. A. Sloane, Mar 20 2010
STATUS
approved