A026993 a(n) = Sum_{k=0..n-2} T(n,k) * T(n,k+2), with T given by A026692.

1, 6, 32, 180, 984, 4606, 22689, 114992, 567129, 2576582, 12586319, 63131004, 305635176, 1384074886, 6739962365, 33708050180, 162468169385, 737652413014, 3588021213950, 17917172173846, 86273708463456, 393163075111278, 1911781914938634, 9536792007640980, 45924386118166540

Offset

2,2

Links

Table of n, a(n) for n=2..26.

Crossrefs

Cf. A026692.

Sequence in context: A000558 A047763 A259621 * A238115 A228959 A302734

Adjacent sequences: A026990 A026991 A026992 * A026994 A026995 A026996

Keyword

nonn

Author

Clark Kimberling

Extensions

More terms from Sean A. Irvine, Oct 21 2019

Status

approved