OFFSET
6,6
LINKS
Alois P. Heinz, Table of n, a(n) for n = 6..1000
MAPLE
b:= proc(n, t, k) option remember; `if`(n=0,
`if`(t in [0, k], 1, 0), `if`(t>n, 0, add(b(j-1, k$2)*
b(n-j, max(0, t-1), k), j=1..n)))
end:
a:= n-> b(n-1, 5$2) -b(n-1, 6$2):
seq(a(n), n=6..50);
MATHEMATICA
b[n_, t_, k_] := b[n, t, k] = If[n == 0,
If[MemberQ[{0, k}, t], 1, 0], If[t > n, 0, Sum[b[j-1, k, k]*
b[n-j, Max[0, t-1], k], {j, n}]]];
a[n_] := b[n-1, 5, 5] - b[n-1, 6, 6];
Table[a[n], {n, 6, 50}] (* Jean-François Alcover, Aug 28 2021, after Maple code *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Joerg Arndt and Alois P. Heinz, Jun 29 2014
STATUS
approved