A246230 Number of compositions of n into exactly three different parts with distinct multiplicities.

60, 285, 498, 1438, 2816, 5208, 11195, 24094, 38523, 85182, 148051, 255922, 512428, 991423, 1573152, 3318750, 5820718, 9712145, 19523028, 36637218, 58805129, 121712569, 216006156, 360123456, 720094287, 1340734558, 2184432420, 4453145090, 7987036106, 13417450294

Offset

10,1

Links

Alois P. Heinz and Vaclav Kotesovec, Table of n, a(n) for n = 10..220 (first 120 terms from Alois P. Heinz)

Mathematica

b[n_, i_, s_List] := b[n, i, s] = If[n == 0, Total[s]!, If[i<1, 0, Expand[ Sum[ If[j>0 && MemberQ[s, j], 0, If[j == 0, 1, x]*b[n-i*j, i-1, If[j == 0, s, s ~Union~{j}]]/j!], {j, 0, n/i}]]]]; a[n_] := Coefficient[b[n, n, {}], x, 3]; Table[a[n], {n, 10, 40}] (* Jean-François Alcover, Feb 11 2015, after Alois P. Heinz *)

Crossrefs

Column k=3 of A242896.

Sequence in context: A328156 A160917 A100154 * A100148 A100151 A338109

Adjacent sequences: A246227 A246228 A246229 * A246231 A246232 A246233

Keyword

nonn

Author

Alois P. Heinz, Aug 19 2014

Status

approved