A026848 a(n) = T(2n,n-4), T given by A026736.

1, 11, 79, 471, 2535, 12809, 62067, 292085, 1345718, 6102780, 27343148, 121359692, 534632836, 2341151646, 10201950700, 44278673806, 191540714294, 826265471868, 3555992623850, 15273547250820, 65491352071266, 280412963707416

Offset

4,2

Comments

Is this the same as A026841? - R. J. Mathar, Oct 23 2008

Column k=10 of triangle A236830. - Philippe Deléham, Feb 02 2014

Links

G. C. Greubel, Table of n, a(n) for n = 4..1000

Formula

a(n) = A026841(n). - Philippe Deléham, Feb 02 2014

G.f.: (x^4*C(x)^10)/(1-x*C(x)^3) where C(x) is the g.f. of A000108. - Philippe Deléham, Feb 02 2014

Mathematica

Drop[CoefficientList[Series[(1-Sqrt[1-4*x])^10/(128*x^4*(8*x^2 -(1 - Sqrt[1-4*x])^3 )), {x, 0, 40}], x], 4] (* G. C. Greubel, Jul 17 2019 *)

Prog

(PARI) my(x='x+O('x^40)); Vec((1-sqrt(1-4*x))^10/(128*x^4*(8*x^2 -(1 - sqrt(1-4*x))^3 ))) \\ G. C. Greubel, Jul 17 2019
(Magma) R<x>:=PowerSeriesRing(Rationals(), 40); Coefficients(R!( (1-Sqrt(1-4*x))^10/(128*x^4*(8*x^2 -(1-Sqrt(1-4*x))^3 )) )); // G. C. Greubel, Jul 17 2019
(Sage) a=((1-sqrt(1-4*x))^10/(128*x^4*(8*x^2 -(1-sqrt(1-4*x))^3 ))).series(x, 45).coefficients(x, sparse=False); a[4:40] # G. C. Greubel, Jul 17 2019

Crossrefs

Cf. A236830.

Sequence in context: A111067 A172067 A026841 * A026864 A243416 A101028

Adjacent sequences: A026845 A026846 A026847 * A026849 A026850 A026851

Keyword

nonn

Author

Clark Kimberling

Status

approved