A139055 Sum of proper divisors of the number of partitions of n.

0, 1, 1, 1, 1, 1, 9, 14, 42, 54, 64, 19, 1, 105, 196, 153, 183, 191, 536, 333, 1548, 1014, 257, 1649, 1282, 4284, 3326, 2870, 1483, 7500, 4390, 4419, 7641, 9866, 7461, 1, 5435, 9097, 38511, 50214, 29913, 33874, 41283, 22041, 47954, 109338, 107806, 77175, 61579, 129998

Offset: 1

Author

Omar E. Pol, Apr 16 2008

Keywords

• nonn

Examples

			a(7) = 9 because the number of partitions of 7 is 15 and the sum of proper divisors of 15 is equal to 1 + 3 + 5 = 9.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000 (calculated from the b-files at A000041 and A001065)

Crossrefs

Cf. A000041, A001065, A139041.

Programs

Mathematica

s[n_] := DivisorSigma[1, n] - n; Array[s[PartitionsP[#]] &, 50] (* Amiram Eldar, Jan 07 2020 *)

PARI

a(n) = my(p=numbpart(n)); sigma(p) - p; \\ Michel Marcus, Jan 07 2020

Formula

a(n) = A001065(A000041(n)).