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.

A066189 Sum of all partitions of n into distinct parts.

Original entry on oeis.org

0, 1, 2, 6, 8, 15, 24, 35, 48, 72, 100, 132, 180, 234, 308, 405, 512, 646, 828, 1026, 1280, 1596, 1958, 2392, 2928, 3550, 4290, 5184, 6216, 7424, 8880, 10540, 12480, 14784, 17408, 20475, 24048, 28120, 32832, 38298, 44520, 51660, 59892, 69230, 79904
Offset: 0

Views

Author

Wouter Meeussen, Dec 15 2001

Keywords

Examples

			The strict integer partitions of 6 are {(6), (5,1), (4,2), (3,2,1)} with sum 6+5+1+4+2+3+2+1 = 24. - _Gus Wiseman_, May 09 2019
		

Crossrefs

Programs

  • Maple
    b:= proc(n, i) option remember; `if`(n=0, [1, 0], `if`(i>n, [0$2],
          b(n, i+1)+(p-> p+[0, i*p[1]])(b(n-i, i+1))))
        end:
    a:= n-> b(n, 1)[2]:
    seq(a(n), n=0..80);  # Alois P. Heinz, Sep 01 2014
  • Mathematica
    PartitionsQ[ Range[ 60 ] ]Range[ 60 ]
    nmax=60; CoefficientList[Series[x*D[Product[1+x^k, {k, 1, nmax}], x], {x, 0, nmax}], x] (* Vaclav Kotesovec, Nov 21 2016 *)

Formula

G.f.: sum(n>=1, n*q^(n-1)/(1+q^n) ) * prod(n>=1, 1+q^n ). - Joerg Arndt, Aug 03 2011
a(n) = n * A000009(n). - Vaclav Kotesovec, Sep 25 2016
G.f.: x*f'(x), where f(x) = Product_{k>=1} (1 + x^k). - Vaclav Kotesovec, Nov 21 2016
a(n) = A056239(A325506(n)). - Gus Wiseman, May 09 2019