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.

A090809 Coefficient of the irreducible character of S_m indexed by (m-2n+2,2n-2) in the n-th Kronecker power of the representation indexed by (m-2,2).

Original entry on oeis.org

0, 0, 2, 10, 31, 75, 155, 287, 490, 786, 1200, 1760, 2497, 3445, 4641, 6125, 7940, 10132, 12750, 15846, 19475, 23695, 28567, 34155, 40526, 47750, 55900, 65052, 75285, 86681, 99325, 113305, 128712, 145640, 164186, 184450, 206535, 230547
Offset: 0

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Author

Alain Goupil, Feb 10 2004

Keywords

Comments

For n > 0, the terms of this sequence are related to A000124 by a(n) = Sum_{i=0..n-1} i*A000124(i). - Bruno Berselli, Dec 20 2013

References

  • A. Goupil, Combinatorics of the Kronecker products of irreducible representations of Sn, in preparation.

Crossrefs

Programs

  • Maple
    f := proc(k) 2*binomial(k,2)+4*binomial(k,3)+3*binomial(k,4); end;
    seq (f(n), n=0..50);
  • Mathematica
    f[n_] := 2Binomial[n, 2] + 4Binomial[n, 3] + 3Binomial[n, 4]; Table[ f[n], {n, 0, 40}] (* Robert G. Wilson v, Feb 13 2004 *)
    LinearRecurrence[{5, -10, 10, -5, 1}, {0, 0, 2, 10, 31}, 38] (* Jean-François Alcover, Sep 25 2017 *)

Formula

a(n) = 2*binomial(n, 2) + 4*binomial(n, 3) + 3*binomial(n, 4) = (n-1)*n*(3*n^2 + n + 10)/24.
a(n) = A049020(n, n-2), for n >= 2. - Philippe Deléham, Mar 06 2004
G.f.: x^2*(2 + x^2) / (1-x)^5. - Colin Barker, Nov 21 2012

Extensions

More terms from Robert G. Wilson v, Feb 13 2004