This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A009074 #15 Sep 08 2022 08:44:37
%S A009074 1,-1,0,2,-12,44,-216,944,-5296,27632,-168128,975072,-5391680,
%T A009074 27882048,38412672,-1986004224,61881368832,-850359527680,
%U A009074 16576603568128,-222801125934592,4120672559178752,-57863671042155520
%N A009074 Expansion of e.g.f. cos(tan(x))/exp(x).
%H A009074 G. C. Greubel, <a href="/A009074/b009074.txt">Table of n, a(n) for n = 0..250</a>
%t A009074 With[{nmax = 30}, CoefficientList[Series[Cos[Tan[x]]/Exp[x], {x, 0, nmax}], x]*Range[0, nmax]!] (* _G. C. Greubel_, Jul 24 2018 *)
%o A009074 (PARI) x='x+O('x^30); Vec(serlaplace(cos(tan(x))/exp(x))) \\ _G. C. Greubel_, Jul 24 2018
%o A009074 (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 A009074 sign,easy
%O A009074 0,4
%A A009074 _R. H. Hardin_
%E A009074 Extended with signs by _Olivier Gérard_, Mar 15 1997