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A102073 Numerators of e.g.f. sec(arccosh(x)) = cosec(arcsinh(x)). 1

%I

%S 1,-1,220,-830,51280,-24271600,2978372800,-72656038000,

%T 6574942704928000,-369025338813664000,439973927875730560000,

%U -16173932272478277440000,8586787143256164544000000

%N Numerators of e.g.f. sec(arccosh(x)) = cosec(arcsinh(x)).

%e sec(arccosh(x)) = 1/x + x/3 - 1/3*x^3/3! + 220/63*x^5/5! - ...

%t terms = 13; s = -1/x + Csc[ArcSinh[x]] + O[x]^(2 terms) // Normal;

%t CoefficientList[s, x] * Range[0, 2 terms - 1]! // DeleteCases[#, 0]& // Numerator (* _Jean-Fran├žois Alcover_, Jul 23 2017 *)

%Y Denominators are in A102074.

%K sign,frac

%O 1,3

%A _Ralf Stephan_, Dec 31 2004

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Last modified January 25 08:35 EST 2022. Contains 350565 sequences. (Running on oeis4.)