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
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Aug 19 2014
STATUS
approved