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

1,7

Links

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

Formula

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

Example

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.

Mathematica

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

Prog

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

Crossrefs

Cf. A000041, A001065, A139041.

Sequence in context: A175201 A066793 A275508 * A294030 A079625 A027009

Adjacent sequences: A139052 A139053 A139054 * A139056 A139057 A139058

Keyword

nonn

Author

Omar E. Pol, Apr 16 2008

Status

approved