A027203 a(n) = Sum_{k=0..n-2} T(n,k) * T(n,k+2), with T given by A026714.

1, 10, 75, 450, 2814, 15202, 89623, 466252, 2677281, 13691160, 77546684, 393047294, 2209036094, 11140807218, 62325916869, 313402240000, 1748294223916, 8775335427968, 48864101440273, 244988564184682, 1362584143931457

Offset

2,2

Links

Table of n, a(n) for n=2..22.

Maple

A027203 := proc(n)
    add( A026714(n, k)*A026714(n, k+2), k=0..n-2) ;
end proc:
seq(A027203(n), n=2..30) ; # R. J. Mathar, Oct 21 2019

Crossrefs

Sequence in context: A283238 A316462 A022734 * A291003 A305784 A053464

Adjacent sequences: A027200 A027201 A027202 * A027204 A027205 A027206

Keyword

nonn

Author

Clark Kimberling

Extensions

Name corrected by Sean A. Irvine, Oct 21 2019

More terms from Ray Chandler, Oct 22 2019

Status

approved