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A128058 Expansion of 1/((1-x)sqrt(1-2x+5x^2)). 2
1, 2, 1, -4, -9, 2, 43, 72, -53, -418, -549, 860, 4161, 4006, -11619, -41104, -24989, 145046, 399571, 89796, -1723259, -3787914, 829841, 19739016, 34642741, -26909998, -219300587, -300591148, 467328447, 2369124842 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Partial sums of A098331. Binomial transform of A128057. Hankel transform is A128056.

LINKS

Table of n, a(n) for n=0..29.

FORMULA

a(n)=sum{k=0..n, sum{j=0..k, C(k,j)*C(k-j,j)*(-1)^j}}

D-finite with recurrence: n*a(n) +(-3*n+1)*a(n-1) +(7*n-6)*a(n-2) +5*(-n+1)*a(n-3)=0. - R. J. Mathar, Jan 23 2020

MATHEMATICA

CoefficientList[Series[1/((1-x)Sqrt[1-2x+5x^2]), {x, 0, 50}], x] (* Harvey P. Dale, Jun 23 2018 *)

CROSSREFS

Sequence in context: A183244 A086933 A077878 * A163236 A325008 A325016

Adjacent sequences:  A128055 A128056 A128057 * A128059 A128060 A128061

KEYWORD

easy,sign

AUTHOR

Paul Barry, Feb 13 2007

STATUS

approved

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Last modified June 21 00:57 EDT 2021. Contains 345329 sequences. (Running on oeis4.)