A053477 Sum of iterates of divisor number function A000005.

1, 2, 5, 9, 7, 15, 9, 17, 14, 19, 13, 27, 15, 23, 24, 23, 19, 33, 21, 35, 30, 31, 25, 41, 30, 35, 36, 43, 31, 47, 33, 47, 42, 43, 44, 50, 39, 47, 48, 57, 43, 59, 45, 59, 60, 55, 49, 67, 54, 65, 60, 67, 55, 71, 64, 73, 66, 67, 61, 87, 63, 71, 78, 73, 74, 83, 69, 83, 78, 87, 73

Offset

1,2

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Example

If n is prime then the iteration sequence is {p,2} and the sum is p+2. If n=30, then iterations of the d function are {30,8,4,3,2} and their sum is a(30)=47.

Maple

f:= proc(n) option remember;
  if n <= 2 then n
  else n + procname(numtheory:-tau(n));
  fi
end proc:
map(f, [$1..80]); # Robert Israel, Nov 14 2016

Mathematica

g[n_] := DivisorSigma[0, n]; f[n_] := Plus @@ Drop[ FixedPointList[g, n], -1]; Table[ f[n], {n, 71}] (* Robert G. Wilson v, Dec 16 2004 *)

Crossrefs

Cf. A000005, A036452, A036453, A036454, A036455, A036459.

Sequence in context: A198429 A089578 A020852 * A104956 A360897 A020820

Adjacent sequences: A053474 A053475 A053476 * A053478 A053479 A053480

Keyword

nonn

Author

Labos Elemer, Jan 14 2000

Status

approved