A294621 Number of partitions of n into generalized heptagonal numbers (A085787).

1, 1, 1, 1, 2, 2, 2, 3, 4, 4, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, 16, 18, 20, 21, 23, 26, 29, 32, 35, 38, 41, 45, 49, 53, 59, 64, 69, 73, 80, 87, 94, 101, 109, 117, 125, 134, 145, 156, 167, 178, 190, 202, 217, 232, 249, 265, 282, 299, 318, 339, 361, 384, 408, 432, 457, 484, 514, 545, 578, 610, 646

Offset: 0

Author

Ilya Gutkovskiy, Nov 05 2017

Keywords

• nonn

Examples

			a(8) = 4 because we have [7, 1], [4, 4], [4, 1, 1, 1, 1] and [1, 1, 1, 1, 1, 1, 1, 1].
		

Links

• Eric Weisstein's World of Mathematics, Heptagonal Number
• Index to sequences related to polygonal numbers
• Index entries for related partition-counting sequences

Crossrefs

Cf. A007294, A085787, A095699, A279012, A294622, A294623.

Programs

Mathematica

nmax = 70; CoefficientList[Series[Product[1/((1 - x^(k (5 k - 3)/2)) (1 - x^(k (5 k + 3)/2))), {k, 1, nmax}], {x, 0, nmax}], x]

Formula

G.f.: Product_{k>=1} 1/((1 - x^(k*(5*k-3)/2))*(1 - x^(k*(5*k+3)/2))).