Expansion of e.g.f.: exp(tan(x))/cos(x).

Terms

a(0) =1a(1) =1a(2) =2a(3) =6a(4) =20a(5) =92a(6) =448a(7) =2688a(8) =17296a(9) =127312a(10) =1013600a(11) =8850336a(12) =83547584a(13) =845380928a(14) =9196867072a(15) =105911556096