Expansion of e.g.f.: 1 + tan(x).

Terms

a(0) =1a(1) =1a(2) =0a(3) =2a(4) =0a(5) =16a(6) =0a(7) =272a(8) =0a(9) =7936a(10) =0a(11) =353792a(12) =0a(13) =22368256a(14) =0a(15) =1903757312a(16) =0a(17) =209865342976a(18) =0a(20) =0a(22) =0a(24) =0a(26) =0a(28) =0a(30) =0