A087180 - OEIS

A087180

Number partition numbers <= P(n) of the form 3*k (P = A000041).

0, 0, 0, 1, 1, 1, 1, 2, 2, 3, 4, 4, 4, 4, 5, 5, 6, 7, 7, 7, 8, 9, 10, 10, 11, 11, 12, 12, 12, 12, 13, 13, 14, 15, 15, 16, 16, 16, 16, 17, 18, 19, 19, 20, 20, 20, 21, 21, 22, 22, 22, 23, 24, 25, 25, 25, 25, 26, 26, 26, 26, 27, 27, 28, 28, 28, 28, 28, 29, 29, 30, 31, 31, 31, 31, 32

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,8

LINKS

Amiram Eldar, Table of n, a(n) for n = 0..10000

Eric Weisstein's World of Mathematics, Partition Function.

Eric Weisstein's World of Mathematics, Partition Function P Congruences.

FORMULA

a(n) + A087181(n) + A087182(n) = n + 1.

MATHEMATICA

Accumulate[Table[Boole[Mod[PartitionsP[n], 3] == 0], {n, 0, 100}]] (* Amiram Eldar, May 22 2025 *)

CROSSREFS