%I
%S 1,0,12,336,2096,1043328,29488704,8894706432,389860902656,
%T 170568226222080,6327905330549760,6080018829202427904,
%U 242897035394043301888,323994054628796940582912,123697309877515731773669376,13142696592417683099946516480
%N Expansion of e.g.f. sin(tanh(x)/cos(x)).
%C Among solutions to a(n)=2n are primes, twice primes (A001747) and also further numbers.
%t Sin[ Tanh[ x ]/Cos[ x ] ] (* Odd Part *)
%o (PARI) x='x+O('x^34); v = Vec(serlaplace(sin(tanh(x)/cos(x)))); vector(#v\2, n, v[2*n1]) \\ _Michel Marcus_, Apr 02 2017
%K sign
%O 0,3
%A _R. H. Hardin_
%E Extended with signs by _Olivier GĂ©rard_, Mar 15 1997
