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A114633
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a(n) = (n+1)*(n+2)/2 * Sum_{k=0..floor(n/2)} n!/(n-2*k)!.
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1
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1, 3, 18, 70, 555, 2961, 31108, 213228, 2799765, 23455135, 369569046, 3659001138, 67261566463, 768390239085, 16142775951240, 209002145031256, 4939689441079593, 71478733600689723, 1877081987610245530, 30021068112289683870, 867211878275933435091, 15190660464818580038473
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OFFSET
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0,2
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COMMENTS
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Related to logarithmic numbers A002104.
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LINKS
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FORMULA
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E.g.f.: exp(x)/(1-x^2)*(x^2/2) (with offset 2). - Zerinvary Lajos, Apr 03 2009
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MAPLE
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a:= n-> (n+1)*(n+2)/2*sum(n!/(n-2*k)!, k=0..floor(n/2)): seq(a(n), n=0..20);
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MATHEMATICA
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Rest[Rest[With[{nn=25}, CoefficientList[Series[Exp[x]/(1 - x^2)(x^2/2), {x, 0, nn}], x] Range[0, nn]!]]] (* Vincenzo Librandi, Sep 03 2017 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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