A134192 a(0) = a(1) = 1. a(n) = Sum_{p|n} a(n-p), where the sum is over all distinct primes p that divide n.

1, 1, 1, 1, 1, 1, 2, 1, 2, 2, 3, 1, 5, 1, 6, 8, 6, 1, 14, 1, 22, 20, 23, 1, 43, 22, 44, 43, 64, 1, 129, 1, 129, 152, 130, 193, 282, 1, 283, 326, 476, 1, 995, 1, 1147, 1471, 1148, 1, 2619, 995, 4090, 2749, 4416, 1, 7165, 5237, 8160, 7448, 8161, 1, 20846, 1, 20847, 29006

Offset

0,7

Links

Table of n, a(n) for n=0..63.

Example

The distinct primes that divide 12 are 2 and 3. So a(12) = a(12-2) + a(12-3) = a(10) + a(9) = 3 + 2 = 5.

Mathematica

a = {1, 1}; For[n = 2, n < 80, n++, s = 0; For[i = 1, i < Length[Divisors[n]] + 1, i++, If[PrimeQ[Divisors[n][[i]]], s = s + a[[n - Divisors[n][[i]] + 1]]]]; AppendTo[a, s]]; a (* Stefan Steinerberger, Aug 30 2008 *)

Crossrefs

Sequence in context: A318717 A331887 A328220 * A358344 A309342 A284044

Adjacent sequences: A134189 A134190 A134191 * A134193 A134194 A134195

Keyword

nonn

Author

Leroy Quet, Jan 13 2008

Extensions

More terms from Stefan Steinerberger, Aug 30 2008

Status

approved