A027993 a(n) = 1*T(n,2n) + 2*T(n,2n-1) + ... + (2n+1)*T(n,0), T given by A027926.

1, 6, 20, 54, 132, 306, 688, 1518, 3308, 7146, 15336, 32742, 69604, 147426, 311264, 655326, 1376220, 2883546, 6029272, 12582870, 26214356, 54525906, 113246160, 234880974, 486539212, 1006632906, 2080374728, 4294967238

Offset

0,2

Links

Table of n, a(n) for n=0..27.

Index entries for linear recurrences with constant coefficients, signature (6,-13,12,-4).

Formula

(n+5)*2^n - 2n - 4, a(0)=1. - Ralf Stephan, Mar 25 2004

G.f. ( 1-3*x^2 ) / ( (2*x-1)^2*(x-1)^2 ). - R. J. Mathar, Jun 12 2013

Mathematica

LinearRecurrence[{6, -13, 12, -4}, {1, 6, 20, 54}, 30] (* Harvey P. Dale, Jun 22 2018 *)

Crossrefs

Cf. A047860.

Sequence in context: A036596 A298408 A038091 * A028492 A059822 A213589

Adjacent sequences: A027990 A027991 A027992 * A027994 A027995 A027996

Keyword

nonn

Author

Clark Kimberling

Status

approved