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.

A271770 Number of set partitions of [n] with minimal block length multiplicity equal to ten.

Original entry on oeis.org

1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 654729075, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1228555090548911125, 55437426478058625, 1034831960923761000, 375268733082243000, 42378561928787584500, 2126522820799377000, 2014348742002209863250, 10413707343032243250
Offset: 10

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Author

Alois P. Heinz, Apr 13 2016

Keywords

Crossrefs

Column k=10 of A271424.

Programs

  • Maple
    with(combinat):
    b:= proc(n, i, k) option remember; `if`(n=0, 1,
          `if`(i<1, 0, add(multinomial(n, n-i*j, i$j)
            *b(n-i*j, i-1, k)/j!, j={0, $k..n/i})))
        end:
    a:= n-> b(n$2, 10)-b(n$2, 11):
    seq(a(n), n=10..40);
  • Mathematica
    multinomial[n_, k_List] := n!/Times @@ (k!);
    b[n_, i_, k_] := b[n, i, k] = If[n == 0, 1, If[i < 1, 0, Sum[multinomial[n, Join[{n - i*j}, Table[i, j]]]*b[n - i*j, i - 1, k]/j!, {j, Join[{0}, Range[k, n/i]]}]]];
    a[n_] := b[n, n, 10] - b[n, n, 11];
    Table[a[n], {n, 10, 40}] (* Jean-François Alcover, May 15 2018, after Alois P. Heinz *)

Formula

a(n) = A271424(n,10).