OFFSET
1,2
COMMENTS
LINKS
Harry J. Smith, Table of n, a(n) for n = 1..1000
MATHEMATICA
lst={}; Do[AppendTo[lst, DivisorSigma[1, DivisorSigma[1, DivisorSigma[1, n]]]], {n, 5!}]; lst (* Vladimir Joseph Stephan Orlovsky, Mar 11 2009 *)
Table[Nest[DivisorSigma[1, #]&, n, 3], {n, 60}] (* Harvey P. Dale, Apr 06 2023 *)
PROG
(PARI) for(n=1, 100, print1(sigma(sigma(sigma(n))), ", ")) \\ Lambert Klasen
(PARI) { for (n=1, 1000, write("b066971.txt", n, " ", sigma(sigma(sigma(n)))) ) } \\ Harry J. Smith, Apr 12 2010
CROSSREFS
KEYWORD
nonn
AUTHOR
Benoit Cloitre, Jan 26 2002
STATUS
approved