A007235 Structure constants for certain representations of S_n. (Formerly M4500)

8, 27, 384, 12100, 736128, 70990416, 9939419136, 1896254551296, 472882821120000, 149328979405056000, 58255835226557644800, 27519543889780053196800, 15483244831426302168268800, 10231838708930053383168000000

Offset

1,1

References

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

Table of n, a(n) for n=1..14.

Alain Goupil, Decomposition of certain products of conjugacy classes of S_n, J. Combin. Theory, A 66 (1994), 102-117.

Formula

a(n) = b(n, 2*n+2) where b(k, m) = (2 * m! / (k^2 * (m-k)^2)) * ((m / (m+1)) * (1 + (-1)^(k+1) / binomial(m, k)) + ((k+1) / binomial(m, k)) * Sum_{j=0..k-1} (j+1) / (binomial(k - 1, j) * binomial(k, j))) [from Goupil]. - Sean A. Irvine, Nov 23 2017

Crossrefs

Sequence in context: A028935 A030089 A348585 * A029789 A155930 A100519

Adjacent sequences: A007232 A007233 A007234 * A007236 A007237 A007238

Keyword

nonn

Author

Simon Plouffe

Extensions

More terms from Sean A. Irvine, Nov 23 2017

Status

approved