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A168416
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a(n) = 1 + 9*floor(n/2).
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1
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1, 10, 10, 19, 19, 28, 28, 37, 37, 46, 46, 55, 55, 64, 64, 73, 73, 82, 82, 91, 91, 100, 100, 109, 109, 118, 118, 127, 127, 136, 136, 145, 145, 154, 154, 163, 163, 172, 172, 181, 181, 190, 190, 199, 199, 208, 208, 217, 217, 226, 226, 235, 235, 244, 244, 253, 253
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OFFSET
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1,2
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LINKS
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FORMULA
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a(n) = 9*n - a(n-1) - 7, with n>1, a(1)=1.
E.g.f.: (1/4)*(9 - 4*exp(x) + (18*x - 5)*exp(2*x))*exp(-x). - G. C. Greubel, Jul 22 2016
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MATHEMATICA
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Table[1 + 9 Floor[n/2], {n, 70}] (* or *) CoefficientList[Series[(1 + 9 x - x^2)/((1 + x) (x - 1)^2), {x, 0, 70}], x] (* Vincenzo Librandi, Sep 19 2013 *)
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PROG
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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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