A027087 a(n) = A027082(n, 2n).

1, 1, 2, 5, 11, 27, 68, 175, 458, 1215, 3258, 8815, 24031, 65937, 181936, 504473, 1404879, 3927495, 11017802, 31004871, 87497297, 247559933, 702089528, 1995483853, 5682959332, 16214622573, 46343364290, 132667706857, 380358924209

Offset

0,3

Links

Table of n, a(n) for n=0..28.

Formula

Conjecture: D-finite with recurrence +3*n*a(n) +3*(-5*n+3)*a(n-1) +(7*n-4)*a(n-2) +(25*n-67)*a(n-3) +(17*n-44)*a(n-4) +(19*n-97)*a(n-5) +(5*n-32)*a(n-6) +3*(n-7)*a(n-7)=0. - R. J. Mathar, Jun 24 2020

Crossrefs

Cf. A027082.

Sequence in context: A340314 A238825 A073225 * A363579 A055227 A325916

Adjacent sequences: A027084 A027085 A027086 * A027088 A027089 A027090

Keyword

nonn

Author

Clark Kimberling

Status

approved