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A026743 a(n) = Sum_{j=0..n} T(n,j), T given by A026736. 2
1, 2, 4, 8, 17, 34, 73, 146, 314, 628, 1350, 2700, 5798, 11596, 24872, 49744, 106573, 213146, 456169, 912338, 1950697, 3901394, 8334539, 16669078, 35582783, 71165566, 151809737, 303619474, 647279131, 1294558262, 2758310121 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..1000

FORMULA

G.f.: ((1-3*x^2)*sqrt((1+2*x)/(1-2*x)) + (1+2*x)*(1+x^2))/(2*(1 -4*x^2 - x^4)). - David Callan, Jan 17 2016

MATHEMATICA

CoefficientList[Normal[Series[((1-3x^2)Sqrt[(1+2x)/(1-2x)] +(1 + 2x)(1+ x^2))/(2(1-4x^2-x^4)), {x, 0, 40}]], x] (* David Callan, Jan 17 2016 *)

PROG

(PARI) my(x='x+O('x^40)); Vec(((1-3*x^2)*sqrt((1+2*x)/(1-2*x)) +(1+2*x)*(1+x^2))/(2*(1-4*x^2-x^4))) \\ G. C. Greubel, Jul 16 2019

(MAGMA) R<x>:=PowerSeriesRing(Rationals(), 40); Coefficients(R!( ((1 -3*x^2)*Sqrt((1+2*x)/(1-2*x)) +(1+2*x)*(1+x^2))/(2*(1-4*x^2-x^4)) )); // G. C. Greubel, Jul 16 2019

(Sage) (((1-3*x^2)*sqrt((1+2*x)/(1-2*x)) + (1+2*x)*(1+x^2))/(2*(1-4*x^2 - x^4))).series(x, 40).coefficients(x, sparse=False) # G. C. Greubel, Jul 16 2019

CROSSREFS

Cf. A026736.

Sequence in context: A266446 A018093 A214083 * A026392 A266897 A018094

Adjacent sequences:  A026740 A026741 A026742 * A026744 A026745 A026746

KEYWORD

nonn

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified October 13 18:57 EDT 2019. Contains 327981 sequences. (Running on oeis4.)