A027317 a(n) = Sum_{k=0..m-2} T(n,k) * T(n,k+2), where m=n for n=0,1,2,3; m=2n for n >= 4; and T is given by A026082.

1, 6, 71, 561, 4797, 41462, 359530, 3124752, 27213084, 237432807, 2075064759, 18162872365, 159198909233, 1397157808149, 12275908402205, 107974903916703, 950639462501475, 8377212510209165, 73882962176311701, 652114141845864819, 5759883148706408695

Offset

2,2

Links

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

Crossrefs

Sequence in context: A050788 A241883 A297746 * A283342 A099339 A213530

Adjacent sequences: A027314 A027315 A027316 * A027318 A027319 A027320

Keyword

nonn

Author

Clark Kimberling

Extensions

More terms from Sean A. Irvine, Oct 27 2019

Status

approved