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Expansion of e.g.f. sin(x)*sin(tan(x)) (even powers only).
2

%I #25 May 02 2024 14:43:16

%S 0,2,0,-32,-1984,-118016,-8529920,-754714880,-79868821504,

%T -9749056634880,-1296267479826432,-165153529347768320,

%U -9993013885707223040,7114872804447958401024,5975166564856692622753792

%N Expansion of e.g.f. sin(x)*sin(tan(x)) (even powers only).

%H G. C. Greubel, <a href="/A009548/b009548.txt">Table of n, a(n) for n = 0..240</a>

%t With[{nmax = 50}, CoefficientList[Series[Sin[x]*Sin[Tan[x]], {x,0,nmax}], x]*Range[0, nmax]!][[1 ;; ;; 2]] (* _G. C. Greubel_, Jan 20 2018 *)

%o (PARI) x='x+O('x^50); v=Vec(serlaplace(sin(x)*sin(tan(x)))); concat([0], vector(#v\2,n,v[2*n-1])) \\ _G. C. Greubel_, Jan 20 2018

%K sign

%O 0,2

%A _R. H. Hardin_

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