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%I #15 Sep 08 2022 08:44:37
%S 1,-1,0,2,-12,44,-216,944,-5296,27632,-168128,975072,-5391680,
%T 27882048,38412672,-1986004224,61881368832,-850359527680,
%U 16576603568128,-222801125934592,4120672559178752,-57863671042155520
%N Expansion of e.g.f. cos(tan(x))/exp(x).
%H G. C. Greubel, <a href="/A009074/b009074.txt">Table of n, a(n) for n = 0..250</a>
%t With[{nmax = 30}, CoefficientList[Series[Cos[Tan[x]]/Exp[x], {x, 0, nmax}], x]*Range[0, nmax]!] (* _G. C. Greubel_, Jul 24 2018 *)
%o (PARI) x='x+O('x^30); Vec(serlaplace(cos(tan(x))/exp(x))) \\ _G. C. Greubel_, Jul 24 2018
%o (Magma) m:=30; R<x>:=PowerSeriesRing(Rationals(), m); b:=Coefficients(R!(Cos(Tan(x))/Exp(x))); [Factorial(n-1)*b[n]: n in [1..m]]; // _G. C. Greubel_, Jul 24 2018
%K sign,easy
%O 0,4
%A _R. H. Hardin_
%E Extended with signs by _Olivier Gérard_, Mar 15 1997