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%I #14 Jul 22 2018 22:53:39
%S 1,-1,-3,27,2425,143031,8956533,618394579,46232494321,3608163168111,
%T 254307747662573,-15725973912655477,-32163339922362247575,
%U -26444005741558393208281,-19705272022676306432282267
%N Expansion of E.g.f. cos(sin(tan(x))), even powers only.
%H G. C. Greubel, <a href="/A009039/b009039.txt">Table of n, a(n) for n = 0..237</a>
%t With[{nmax = 60}, CoefficientList[Series[Cos[Sin[Tan[x]]], {x, 0, nmax}], x]*Range[0, nmax]!][[1 ;; -1 ;; 2]] (* _G. C. Greubel_, Jul 22 2018 *)
%o (PARI) x='x+O('x^60); v=Vec(serlaplace(cos(sin(tan(x))))); vector(#v\2,n,v[2*n-1]) \\ _G. C. Greubel_, Jul 22 2018
%K sign
%O 0,3
%A _R. H. Hardin_
%E Extended with signs by _Olivier Gérard_, Mar 15 1997