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A147601
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First differences of A132355.
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1
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7, 4, 21, 8, 35, 12, 49, 16, 63, 20, 77, 24, 91, 28, 105, 32, 119, 36, 133, 40, 147, 44, 161, 48, 175, 52, 189, 56, 203, 60, 217, 64, 231, 68, 245, 72, 259, 76, 273, 80, 287, 84, 301, 88, 315, 92, 329, 96, 343, 100, 357
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OFFSET
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0,1
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LINKS
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FORMULA
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G.f.: ( 7+4*x+7*x^2 ) / ((1-x)*(1+x))^2. - R. J. Mathar, Jun 21 2011
a(2*n+1) = 4*(n+1).
E.g.f.: (1/2)*(5*(1-x)*exp(-x) + 9*(1+x)*exp(x)). - G. C. Greubel, Oct 25 2022
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MATHEMATICA
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Differences[Sort[Table[9n^2+2n, {n, -30, 30}]]] (* or *) LinearRecurrence[ {0, 2, 0, -1}, {7, 4, 21, 8}, 60] (* Harvey P. Dale, Jun 04 2017 *)
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PROG
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(Magma) [(9 + 5*(-1)^n)*(1+n)/2: n in [0..60]]; // G. C. Greubel, Oct 25 2022
(SageMath) [(9 + 5*(-1)^n)*(1+n)/2 for n in range(61)] # G. C. Greubel, Oct 25 2022
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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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STATUS
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approved
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