OFFSET
0,4
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..480
MAPLE
b:= proc(n, i, k) option remember; `if`(i*(i+1)/2<n, 0, `if`(n=0 or
k=0, 1, b(n, i-1, k)+b(i$2, k-1)*b(n-i, min(n-i, i-1), k)))
end:
a:= n-> b(n$3):
seq(a(n), n=0..25);
MATHEMATICA
b[n_, i_, k_] := b[n, i, k] = If[i(i+1)/2 < n, 0, If[n == 0 || k == 0, 1, b[n, i - 1, k] + b[i, i, k - 1] b[n - i, Min[n - i, i - 1], k]]];
a[n_] := b[n, n, n];
a /@ Range[0, 25] (* Jean-François Alcover, Dec 08 2020, after Alois P. Heinz *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Jan 27 2019
STATUS
approved