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.

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A309972 Product of multinomial coefficients M(n;lambda), where lambda ranges over all partitions of n.

Original entry on oeis.org

1, 1, 2, 18, 6912, 216000000, 1632586752000000000, 498266101635303733401600000000000, 1140494258799407218656986754465090350453096448000000000000000
Offset: 0

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Author

Alois P. Heinz, Aug 25 2019

Keywords

Examples

			a(3) = M(3;3) * M(3;2,1) * M(3;1,1,1) = 1 * 3 * 6 = 18.
		

Crossrefs

Rightmost terms in rows of A309951.

Programs

  • Maple
    b:= proc(n, i) option remember; `if`(n=0 or i=1, [n!], [map(t->
          binomial(n, i)*t, b(n-i, min(n-i, i)))[], b(n, i-1)[]])
        end:
    a:= n-> mul(i, i=b(n$2)):
    seq(a(n), n=0..9);  # Alois P. Heinz, Aug 25 2019
  • Mathematica
    b[n_, i_] := b[n, i] = If[n == 0 || i == 1, {n!}, Join[Binomial[n, i] #& /@ b[n - i, Min[n - i, i]], b[n, i - 1]]];
    a[n_] := Times @@ b[n, n];
    a /@ Range[0, 9] (* Jean-François Alcover, Dec 07 2020, after Alois P. Heinz *)

Formula

a(n) = Product_{k=1..A000041(n)} A036038(n,k).
a(n) = A309951(n,A000041(n)).
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