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A127017
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Expansion of 1/(1+6*x*c(x)), where c(x) = g.f. for Catalan numbers A000108.
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6
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1, -6, 30, -156, 798, -4116, 21132, -108792, 559134, -2876772, 14790660, -76080648, 391221516, -2012174664, 10347690072, -53218984176, 273689323038, -1407575396484, 7238848057812, -37228770844776, 191460735261828, -984660836306904, 5063949044206632, -26043244926688656
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OFFSET
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0,2
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COMMENTS
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Hankel transform is (-6)^n.
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LINKS
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FORMULA
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a(n) = Sum_{k=0..n} A039599(n,k)*(-7)^k.
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MAPLE
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c:=(1-sqrt(1-4*x))/2/x: ser:=series(1/(1+6*x*c), x=0, 27): seq(coeff(ser, x, n), n=0..23); # Emeric Deutsch, Mar 23 2007
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MATHEMATICA
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CoefficientList[Series[1/(4-3*Sqrt[1-4*x]), {x, 0, 30}], x] (* G. C. Greubel, May 31 2019 *)
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PROG
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(PARI) my(x='x+O('x^30)); Vec(1/(4-3*sqrt(1-4*x))) \\ G. C. Greubel, May 31 2019
(Magma) R<x>:=PowerSeriesRing(Rationals(), 30); Coefficients(R!( 1/(4 - 3*Sqrt(1-4*x)) )); // G. C. Greubel, May 31 2019
(Sage) (1/(4-3*sqrt(1-4*x))).series(x, 30).coefficients(x, sparse=False) # G. C. Greubel, May 31 2019
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CROSSREFS
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KEYWORD
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sign
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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