OFFSET
1,2
COMMENTS
Repeated application of tau (number of divisors) and sigma (sum of divisors).
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..10000
MAPLE
with(numtheory) : A163106 := proc(n) sigma(sigma(tau(n))) ; end: seq(A163106(n), n=1..120) ; # R. J. Mathar, Jul 27 2009
MATHEMATICA
DivisorSigma[1, DivisorSigma[1, DivisorSigma[0, Range[90]]]] (* Harvey P. Dale, Oct 14 2017 *)
PROG
(PARI) A163106(n) = sigma(sigma(numdiv(n))); \\ Antti Karttunen, May 25 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Jul 20 2009
EXTENSIONS
More terms from R. J. Mathar, Jul 27 2009
STATUS
approved