cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A286929 Number of partitions of n such that each part is no more than 3 more than the sum of all smaller parts.

Original entry on oeis.org

1, 1, 2, 3, 4, 6, 9, 13, 17, 25, 33, 46, 61, 84, 108, 147, 187, 248, 316, 414, 519, 675, 843, 1077, 1339, 1699, 2090, 2633, 3227, 4020, 4909, 6076, 7369, 9075, 10965, 13394, 16129, 19613, 23493, 28434, 33954, 40858, 48643, 58301, 69124, 82547, 97593, 116017, 136804, 162101, 190504
Offset: 0

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Author

Brian Hopkins, May 16 2017

Keywords

Comments

Generalization of Adams-Watters's criterion for complete partitions, that each part is no more than 1 more than the sum of all smaller parts.
Also the number of complete partitions of n+1 that contain more than one 1. - George Beck, Oct 01 2017

Examples

			For n = 8, a(8) = 17 counts all partitions of 8 except (8), (7,1), (6,2), (6,1,1), and (4,4).
		

Crossrefs

Cf. A126796.

Programs

  • Mathematica
    Table[Count[IntegerPartitions@ n, w_ /; And[Last@ w <= 3, NoneTrue[w - Rest@ PadRight[3 + Reverse@ Accumulate@ Reverse@ w, Length@ w + 1, Last@ w], # > 0 &]]], {n, 50}] (* Michael De Vlieger, May 16 2017, Version 10 *)

Formula

a(n) ~ exp(Pi*sqrt(2*n/3)) / (4*sqrt(3)*n). - Vaclav Kotesovec, May 24 2018