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A131281
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Expansion of e.g.f.: 2*(x-1)*tan(x/2+Pi/4)-x^2+2.
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2
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0, 0, 0, 2, 6, 18, 70, 310, 1582, 9058, 57678, 403878, 3085478, 25535378, 227589206, 2173314806, 22137209694, 239580726978, 2745392996254, 33207657441094, 422813028038230, 5652593799727858, 79168165551184422, 1159200449070638742, 17711278225214739086
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OFFSET
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0,4
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LINKS
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FORMULA
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E.g.f. E(x)=2*(x-1)*tan(x/2+Pi/4)-x^2+2 = 2*x - x^2 + 4*x*(x-1)/(Q(0)-x) where Q(k) = 4*k + 2 - x^2/Q(k+1); (continued fraction, 1-step).- Sergei N. Gladkovskii, Jun 22 2012
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MATHEMATICA
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With[{nn=30}, CoefficientList[Series[2(x-1)Tan[x/2+Pi/4]-x^2+2, {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Jun 11 2023 *)
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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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