3,2
Alois P. Heinz, Table of n, a(n) for n = 3..458
a(n) = A262165(n) - A262164(n).
b:= proc(u, o, c, k) option remember;
`if`(c<0 or c>k, 0, `if`(u+o=0, 1,
add(b(u-j, o-1+j, c+1, k), j=1..u)+
add(b(u+j-1, o-j, c-1, k), j=1..o)))
end:
a:= n-> b(n, 0$2, 3)-b(n, 0$2, 2):
seq(a(n), n=3..23);
Column k=3 of A258829.
Cf. A262164, A262165.
Sequence in context: A338791 A100019 A053132 * A048367 A095665 A145346
Adjacent sequences: A316387 A316388 A316389 * A316391 A316392 A316393
nonn
Alois P. Heinz, Jul 01 2018
approved
