A246231 Number of compositions of n into exactly four different parts with distinct multiplicities.

12600, 78120, 189000, 549000, 1389960, 2858640, 6471699, 15289662, 29639082, 64025820, 134997382, 267550925, 545274648, 1161661901, 2223888268, 4552401195, 9185643748, 17829746962, 35102264675, 71613947350, 135793314152, 270167493481, 534784841445

Offset

20,1

Links

Alois P. Heinz and Vaclav Kotesovec, Table of n, a(n) for n = 20..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, 4]; Table[a[n], {n, 20, 50}] (* Jean-François Alcover, Feb 11 2015, after Alois P. Heinz *)

Crossrefs

Column k=4 of A242896.

Sequence in context: A237086 A190109 A272516 * A248709 A352586 A261860

Adjacent sequences: A246228 A246229 A246230 * A246232 A246233 A246234

Keyword

nonn

Author

Alois P. Heinz, Aug 19 2014

Status

approved