A055219 T(2n+3,n), array T as in A055216.

1, 5, 21, 78, 274, 927, 3061, 9933, 31824, 100972, 317942, 995088, 3099105, 9612735, 29715525, 91595391, 281643480, 864189486, 2646805668, 8093543439, 24713953515, 75370741506, 229604257846, 698754428388, 2124616182139

Offset

0,2

Links

Table of n, a(n) for n=0..24.

Formula

Apparently a(n)=sum((-1)^j*binomial(n+3, j)*binomial(2n+3-3j, n+3), j=0..floor(n/3)). - Emeric Deutsch, Mar 13 2004

Crossrefs

Sequence in context: A272787 A084780 A268202 * A108863 A027172 A244198

Adjacent sequences: A055216 A055217 A055218 * A055220 A055221 A055222

Keyword

nonn

Author

Clark Kimberling, May 07 2000

Status

approved