A109932 a(n) = f^n(n) = f applied n times to n, where f(n) = A007425(n).

1, 3, 3, 9, 3, 6, 3, 9, 6, 6, 3, 18, 3, 6, 9, 9, 3, 18, 3, 18, 9, 6, 3, 9, 6, 6, 6, 18, 3, 6, 3, 9, 9, 6, 9, 36, 3, 6, 9, 9, 3, 6, 3, 18, 18, 6, 3, 18, 6, 18, 9, 18, 3, 9, 9, 9, 9, 6, 3, 6, 3, 6, 18, 18, 9, 6, 3, 18, 9, 6, 3, 9, 3, 6, 18, 18, 9, 6, 3, 18, 6, 6, 3, 6, 9, 6, 9, 9, 3, 6, 9, 18, 9, 6, 9, 18

Offset: 1

Author

Amarnath Murthy, Jul 18 2005

Keywords

• nonn

References

• Amarnath Murthy and Mihaly Bencze [Beneze], Extending the scope of some number theoretic functions, Octogon Mathematical Magazine, 2003, Brasov, Romania.

Links

• Antti Karttunen, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A007425.

Programs

Mathematica

f[n_] := Plus @@ DivisorSigma[0, Divisors[n]]; Table[ Nest[f, n, n], {n, 96}] (* Robert G. Wilson v *)

PARI

A007425(n) = sumdivmult(n, k, numdiv(k)); \\ Charles R Greathouse IV, Aug 30 2013
A109932(n) = { my(k=n); while(n, n--; k = A007425(k)); k; }; \\ Antti Karttunen, Sep 22 2017

Extensions

More terms from Robert G. Wilson v, Jul 21 2005

Name edited by Antti Karttunen, Sep 22 2017