OFFSET
7,2
LINKS
Alois P. Heinz, Table of n, a(n) for n = 7..1000
MAPLE
b:= proc(n, i, t, k) option remember; `if`(n=0, 1,
`if`(i<1, 0, add(binomial(b(i-1$2, k$2), j)*
b(n-i*j, i-1, t-j, k), j=0..min(t, n/i))))
end:
a:= n-> b(n-1$2, 3$2) -b(n-1$2, 2$2):
seq(a(n), n=7..60);
MATHEMATICA
b[n_, i_, t_, k_] := b[n, i, t, k] = If[n == 0, 1, If[i<1, 0, Sum[Binomial[ b[i-1, i-1, k, k], j]*b[n - i*j, i-1, t - j, k], {j, 0, Min[t, n/i]}]]];
a[n_] := b[n-1, n-1, 3, 3] - b[n-1, n-1, 2, 2];
Table[a[n], {n, 7, 60}] (* Jean-François Alcover, Aug 28 2021, after Maple code *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Joerg Arndt and Alois P. Heinz, Jul 31 2014
STATUS
approved
