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A168236
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a(n) = (6*n - 3*(-1)^n - 1)/4.
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4
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2, 2, 5, 5, 8, 8, 11, 11, 14, 14, 17, 17, 20, 20, 23, 23, 26, 26, 29, 29, 32, 32, 35, 35, 38, 38, 41, 41, 44, 44, 47, 47, 50, 50, 53, 53, 56, 56, 59, 59, 62, 62, 65, 65, 68, 68, 71, 71, 74, 74, 77, 77, 80, 80, 83, 83, 86, 86, 89, 89, 92, 92, 95, 95, 98, 98, 101, 101, 104, 104
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OFFSET
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1,1
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COMMENTS
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LINKS
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FORMULA
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G.f.: x*(2 + x^2) / ( (1+x)*(x-1)^2 ).
E.g.f.: (1/4)*(-3 + 4*exp(x) + (6*x - 1)*exp(2*x))*exp(-x). - G. C. Greubel, Jul 16 2016
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MATHEMATICA
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CoefficientList[Series[(2 + x^2) / ((1 + x) (x - 1)^2), {x, 0, 70}], x] (* Vincenzo Librandi, Sep 16 2013 *)
Table[(6*n - 3*(-1)^n - 1)/4, {n, 1, 50}] (* or *) LinearRecurrence[ {1, 1, -1}, {2, 2, 5}, 50] (* G. C. Greubel, Jul 16 2016 *)
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PROG
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CROSSREFS
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KEYWORD
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nonn,easy,less
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AUTHOR
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STATUS
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approved
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