OFFSET
0,3
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..449
FORMULA
a(n) ~ exp(3) * n!. - Vaclav Kotesovec, Sep 22 2016
MATHEMATICA
b[n_, m_, l_List] := b[n, m, l] = If[n == 0, m!, Sum[b[n - 1, Max[m, j], Append[ReplacePart[l, 1 -> Nothing], If[j <= m, 0, j]]], {j, Append[l, m + 1] ~Complement~ {0}}]]; a[n_] := b[n, 0, {0, 0, 0}]; Table[a[n], {n, 0, 21}] (* Jean-François Alcover, Jul 18 2017, after Alois P. Heinz *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Sep 21 2016
STATUS
approved