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 A009094 Expansion of e.g.f. cos(tanh(x)*tan(x)) (only powers that are multiples of 4). 1

%I #21 Jul 26 2018 07:44:24

%S 1,-12,-4592,-6274752,18138366208,2332645761266688,

%T 202540305420145266688,24977439274944176331767808,

%U 4480212151308993274762821173248,1107507319145672023044777103840247808,336310686770623540666061200154740824997888

%N Expansion of e.g.f. cos(tanh(x)*tan(x)) (only powers that are multiples of 4).

%H G. C. Greubel, <a href="/A009094/b009094.txt">Table of n, a(n) for n = 0..120</a>

%t With[{nn=60},Select[CoefficientList[Series[Cos[Tanh[x]Tan[x]],{x,0,nn}],x]Range[0,nn]!,#!=0&]] (* _Harvey P. Dale_, Dec 28 2012 *)

%o (PARI) x='x+O('x^80); v=Vec(serlaplace(cos(tanh(x)*tan(x)))); vector(#v\4, n, v[4*n-3]) \\ _G. C. Greubel_, Jul 25 2018

%K sign

%O 0,2

%A _R. H. Hardin_

%E Extended with signs by _Olivier GĂ©rard_, Mar 15 1997

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Last modified May 21 14:18 EDT 2024. Contains 372738 sequences. (Running on oeis4.)