%I #23 Sep 17 2022 14:22:54
%S 0,2,-4,38,-3144,-49526,-10349516,-460714706,-91894143376,
%T -6277401116142,-1574511126111380,-81923064774031562,
%U -27289817479229247448,10031662078758108490394,3820037980300331336027556,3713233478960254473261772350,1785602965553070049822150781152
%N Expansion of e.g.f.: tanh(x)*sin(tan(x)) (even part).
%H Stefano Spezia, <a href="/A009834/b009834.txt">Table of n, a(n) for n = 0..200</a>
%t nmax=200; expan=Series[Tanh[x]*Sin[Tan[x]]/2, {x, 0, 2*nmax}]; Join[{0}, Table[(2n)! Coefficient[expan, x^(2n)], {n, nmax}]] (* _Stefano Spezia_, Sep 17 2022 *)
%o (PARI) my(x='x+O('x^50), v=Vec(serlaplace(tanh(x)*sin(tan(x))))); concat(0, vector(#v\2, k, v[2*k-1])) \\ _Michel Marcus_, Sep 17 2022
%Y Twice A024229.
%K sign
%O 0,2
%A _R. H. Hardin_
%E Extended with signs by _Olivier GĂ©rard_, Mar 15 1997