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A091055
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Expansion of x*(1-2*x)/((1-x)*(1+2*x)*(1-6*x)).
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3
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0, 1, 3, 23, 127, 783, 4655, 28015, 167919, 1007855, 6046447, 36280047, 217677551, 1306070767, 7836413679, 47018503919, 282110979823, 1692665966319, 10155995623151, 60935974088431, 365615843831535, 2193695064387311
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OFFSET
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0,3
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COMMENTS
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Number of walks of length n between adjacent vertices of the Johnson graph J(5,2).
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LINKS
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FORMULA
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a(n) = (3*6^n - 5*(-2)^n + 2)/30.
E.g.f.: (3*exp(6*x) - 5*exp(-2*x) + 2*exp(x))/30. - G. C. Greubel, Dec 27 2019
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MAPLE
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seq( (3*6^n -5*(-2)^n +2)/30, n=0..30); # G. C. Greubel, Dec 27 2019
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MATHEMATICA
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Table[(3*6^n -5*(-2)^n +2)/30, {n, 0, 30}] (* G. C. Greubel, Dec 27 2019 *)
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PROG
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(PARI) vector(31, n, (3*6^(n-1) -5*(-2)^(n-1) +2)/30) \\ G. C. Greubel, Dec 27 2019
(Magma) [(3*6^n -5*(-2)^n +2)/30: n in [0..30]]; // G. C. Greubel, Dec 27 2019
(Magma) R<x>:=PowerSeriesRing(Integers(), 25); [0] cat Coefficients(R!( x*(1-2*x)/((1-x)*(1+2*x)*(1-6*x)))); // Marius A. Burtea, Dec 30 2019
(Sage) [(3*6^n -5*(-2)^n +2)/30 for n in (0..30)] # G. C. Greubel, Dec 27 2019
(GAP) List([0..30], n-> (3*6^n -5*(-2)^n +2)/30); # G. C. Greubel, Dec 27 2019
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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