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.

A327677 Number of colored compositions of n using all colors of an n-set such that any part i has a color pattern of i (distinct) colors in increasing order.

Original entry on oeis.org

1, 1, 3, 13, 71, 481, 3861, 35743, 373591, 4347103, 55671713, 777540523, 11754153869, 191114449579, 3324296885339, 61575268263193, 1209681079172663, 25116819005925409, 549458325556099551, 12629191765880480035, 304232436498153748441, 7663883684722855430077
Offset: 0

Views

Author

Alois P. Heinz, Sep 21 2019

Keywords

Examples

			a(3) = 13: 3abc, 2ab1c, 2ac1b, 2bc1a, 1a2bc, 1b2ac, 1c2ab, 1a1b1c, 1a1c1b, 1b1a1c, 1b1c1a, 1c1a1b, 1c1b1a.
		

Crossrefs

Cf. A261774.

Programs

  • Maple
    b:= proc(n, i, p) option remember; `if`(n=0, p!, `if`(i<1, 0,
          add(b(n-i*j, i-1, p+j)*binomial(n, i*j), j=0..n/i)))
        end:
    a:= n-> b(n$2, 0):
    seq(a(n), n=0..23);
  • Mathematica
    b[n_, i_, p_] := b[n, i, p] = If[n == 0, p!, If[i < 1, 0,
         Sum[b[n - i*j, i - 1, p + j]*Binomial[n, i*j], {j, 0, n/i}]]];
    a[n_] := b[n, n, 0];
    Table[a[n], {n, 0, 23}] (* Jean-François Alcover, Aug 01 2021, after Alois P. Heinz *)