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A131869
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Expansion of series reversion of x*(1-8*x)/(1-x).
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4
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1, 7, 105, 1967, 41265, 927479, 21838425, 531731935, 13278739425, 338235642983, 8753720757705, 229531493157519, 6084679071674385, 162802128960940119, 4390789738688043705, 119242319290800424383, 3258012200816503807425, 89495966923044854350535, 2470171286283446551216425
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OFFSET
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1,2
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COMMENTS
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The Hankel transform of this sequence is 56^C(n+1,2) .
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LINKS
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FORMULA
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a(n) = Sum_{k=0..n} A086810(n,k)*7^k.
G.f.: (x-15-sqrt(x^2-30*x+1))/16.
Recurrence: n*a(n) = 15*(2*n-3)*a(n-1) - (n-3)*a(n-2).
a(n) ~ sqrt(30*sqrt(14)-112)*(15+4*sqrt(14))^n/(16*sqrt(Pi)*n^(3/2)). (End)
G.f.: x/(1 - 7*x/(1 - 8*x/(1 - 7*x/(1 - 8*x/(1 - 7*x/(1 - ...)))))), a continued fraction. - Ilya Gutkovskiy, Apr 20 2017
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MATHEMATICA
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Rest[CoefficientList[InverseSeries[Series[x*(1-8*x)/(1-x), {x, 0, 20}], x], x]] (* Vaclav Kotesovec, Aug 20 2013 *)
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PROG
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(PARI) Vec(serreverse(x*(1-8*x)/(1-x)+O(x^66))) /* Joerg Arndt, Feb 06 2013 */
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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