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A108781

Expansion of sqrt((1-x+8*x^2)/(1-x)^3).

1, 1, 5, 9, 5, -7, 5, 73, 69, -295, -571, 1321, 4613, -4167, -32635, -1783, 211141, 200601, -1229243, -2468375, 6117509, 22557305, -21519611, -176980023, -13664955, 1234115673, 1250908869, -7608051031, -16094268667, 39424807225, 153179607429, -139981878647, -1243776268859

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OFFSET

0,3

LINKS

Table of n, a(n) for n=0..32.

N. Heninger, E. M. Rains and N. J. A. Sloane, On the Integrality of n-th Roots of Generating Functions, arXiv:math/0509316 [math.NT], 2005-2006.

N. Heninger, E. M. Rains and N. J. A. Sloane, On the Integrality of n-th Roots of Generating Functions, J. Combinatorial Theory, Series A, 113 (2006), 1732-1745.

FORMULA

D-finite with recurrence: n*a(n) +(-2*n+1)*a(n-1) +(9*n-25)*a(n-2) +4*(-2*n+5)*a(n-3)=0. - R. J. Mathar, Jan 24 2020

MATHEMATICA

CoefficientList[Series[Sqrt[(1-x+8x^2)/(1-x)^3], {x, 0, 50}], x] (* Harvey P. Dale, Dec 24 2018 *)

PROG

(Magma) m:=40; R<x>:=PowerSeriesRing(Rationals(), m); Coefficients(R!(Sqrt((1-x+8*x^2)/(1-x)^3))); // Vincenzo Librandi, Jan 25 2020

CROSSREFS

Square root of g.f. for A054552.

Sequence in context: A256593 A275810 A302708 * A197693 A117014 A200283

Adjacent sequences: A108778 A108779 A108780 * A108782 A108783 A108784

KEYWORD

sign

AUTHOR

N. J. A. Sloane and Nadia Heninger, Jun 28 2005

STATUS

approved