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.

A208477 Difference between the sum of odd parts and the sum of even parts in all the partitions of n.

Original entry on oeis.org

0, 1, 0, 5, 0, 11, 6, 25, 12, 50, 40, 96, 80, 173, 170, 320, 316, 545, 590, 930, 1020, 1552, 1760, 2537, 2900, 4066, 4736, 6450, 7540, 10045, 11856, 15482, 18280, 23555, 27920, 35461, 42032, 52805, 62662, 77955, 92380, 113963, 135040, 165295, 195540, 237866
Offset: 0

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Author

Omar E. Pol, Mar 10 2012

Keywords

Crossrefs

Programs

  • Maple
    b:= proc(n,i) option remember; local g, h;
          if n=0 then [1, 0]
        elif i<1 then [0, 0]
        else g:= b(n, i-1);
             h:= `if`(i>n, [0, 0], b(n-i, i));
             [g[1]+h[1], g[2]+h[2] +h[1]*i*(2*(i mod 2)-1)]
          fi
        end:
    a:= n-> b(n, n)[2]:
    seq(a(n), n=0..60); # Alois P. Heinz, Mar 10 2012
  • Mathematica
    Map[Total[Select[#, OddQ]] - Total[Select[#, EvenQ]] &[Flatten[IntegerPartitions[#]]] &, -1 + Range[30]] (* Peter J. C. Moses, Mar 14 2014 *)
    max = 60; s = Sum[x^(2i) (x^(2i) - 2i (x-1) - 1)/(x + x^(4i) - (x+1) x^(2i) ), {i, 1, Floor[max/2]}]/QPochhammer[x] + O[x]^max; CoefficientList[s, x] (* Jean-François Alcover, Aug 29 2016, after Alois P. Heinz *)

Formula

a(n) = A066967(n) - A066966(n).
G.f.: (Sum_{i>0} (2*i-1)*x^(2*i-1)/(1-x^(2*i-1))-2*i*x^(2*i)/(1-x^(2*i))) / Product_{j>0} (1-x^j). - Alois P. Heinz, Mar 10 2012

Extensions

More terms from Alois P. Heinz, Mar 10 2012