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A009131
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Expansion of e.g.f. cosh(log(1+x))/cosh(x).
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1
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1, 0, 0, -3, 11, -30, 194, -1785, 13957, -113148, 1143284, -13131855, 156950639, -2005222362, 28119703702, -424785970245, 6792043718345, -115135087505400, 2072993596779944, -39432571052652315, 788564865102950035
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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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MATHEMATICA
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CoefficientList[Series[((1 + (1 + x)^2)*Sech[x])/(2*(1 + x)), {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Jan 22 2015 *)
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PROG
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(PARI) x='x+O('x^30); Vec(serlaplace(cosh(log(1+x))/cosh(x))) \\ G. C. Greubel, Jul 28 2018
(Magma) m:=30; R<x>:=PowerSeriesRing(Rationals(), m); b:=Coefficients(R!(Cosh(Log(1+x))/Cosh(x))); [Factorial(n-1)*b[n]: n in [1..m]]; // G. C. Greubel, Jul 28 2018
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CROSSREFS
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KEYWORD
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sign,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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