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A135138
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a(n) = 5*a(n-2) + 2*a(n-3).
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4
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0, 0, 1, 0, 5, 2, 25, 20, 129, 150, 685, 1008, 3725, 6410, 20641, 39500, 116025, 238782, 659125, 1425960, 3773189, 8448050, 21717865, 49786628, 125485425, 292368870, 727000381, 1712815200, 4219739645, 10018076762, 24524328625, 58529863100
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OFFSET
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0,5
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COMMENTS
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a(n+2), n>=0, is the (5,2)-Padovan sequence p(5,2;n)with o.g.f. 1/(1-5*x^2-2*x^3). See A000931(n+3) ((1,1)-Padovan), and the W. Lang link given there, also for a combinatorial interpretation. - Wolfdieter Lang, Jun 28 2010
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LINKS
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FORMULA
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O.g.f.: -x^2 / ( (2*x+1)*(x^2+2*x-1) ).
a(n) = [(-2)^n + A078343(n)]/7. (End)
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MATHEMATICA
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a = {0, 0, 1}; Do[AppendTo[a, 5*a[[ -2]] + 2*a[[ -3]]], {40}]; a (* Stefan Steinerberger, Feb 15 2008 *)
LinearRecurrence[{0, 5, 2}, {0, 0, 1}, 100] (* G. C. Greubel, Sep 28 2016 *)
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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