A009553 - OEIS

%I #22 May 02 2024 14:46:46

%S 1,2,-4,-176,-1712,66912,4737344,53926656,-18559434496,-1869838374400,

%T 35429689535488,36301265658269696,4137398544580202496,

%U -569857298193726644224,-297369786811582548131840

%N Expansion of e.g.f. sin(x)/cos(sin(x)) (odd powers only).

%H G. C. Greubel, <a href="/A009553/b009553.txt">Table of n, a(n) for n = 0..248</a>

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

%o (PARI) x='x+O('x^50); v=Vec(serlaplace(sin(x)/cos(sin(x)))); vector((#v-1)\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 Gérard_, Mar 15 1997