A167211 Numbers k such that number of perfect partitions of k-1 divides k.

1, 2, 3, 4, 5, 6, 7, 8, 11, 13, 15, 16, 17, 19, 21, 23, 29, 31, 32, 33, 37, 39, 40, 41, 43, 47, 48, 51, 53, 57, 59, 61, 64, 67, 69, 71, 73, 78, 79, 83, 87, 89, 93, 97, 101, 103, 107, 109, 111, 113, 123, 127, 128, 129, 130, 131, 132, 137, 139, 141, 149, 151, 157

Offset: 1

Author

Juri-Stepan Gerasimov, Oct 30 2009

Keywords

• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A002033, A007694, A033950.

Programs

Mathematica

f[1] = 1; f[n_] := f[n] = DivisorSum[n, f[#] &, # < n &]; Select[Range[100], Divisible[#, f[#]] &] (* Amiram Eldar, Dec 30 2019 *)

Formula

{n: A002033(n-1) | n}.

Extensions

Definition corrected by R. J. Mathar, May 21 2010

More terms from Amiram Eldar, Dec 30 2019