A026633 T(n,0) + T(n,1) + ... + T(n,n), T given by A026626.

1, 2, 5, 10, 22, 44, 90, 180, 362, 724, 1450, 2900, 5802, 11604, 23210, 46420, 92842, 185684, 371370, 742740, 1485482, 2970964, 5941930, 11883860, 23767722, 47535444, 95070890, 190141780, 380283562, 760567124, 1521134250

Offset

0,2

Links

Table of n, a(n) for n=0..30.

Index entries for linear recurrences with constant coefficients, signature (2,1,-2).

Formula

G.f.: [1+x^4]/[(1-2x)(1-x^2)]. - Ralf Stephan, Apr 30 2004

a(n) = (-1)^n/3 -1 +17*2^(n-2)/3, n>=2. - R. J. Mathar, May 22 2013

a(n) = a(n-1) + 2*a(n-2) + 2. - Greg Dresden, Feb 22 2020

E.g.f.: (3 + 6*x - 8*cosh(x) + 17*cosh(2*x) - 16*sinh(x) + 17*sinh(2*x))/12. - Stefano Spezia, Feb 22 2020

Crossrefs

Row sums of A026626.

Sequence in context: A097096 A073777 A215422 * A093370 A094537 A135098

Adjacent sequences: A026630 A026631 A026632 * A026634 A026635 A026636

Keyword

nonn

Author

Clark Kimberling

Status

approved