Expansion of e.g.f. exp(2x)*sech(x).

Terms

a(0) =1a(1) =2a(2) =3a(3) =2a(4) =-3a(5) =2a(6) =63a(7) =2a(8) =-1383a(9) =2a(10) =50523a(11) =2a(12) =-2702763a(13) =2a(14) =199360983a(15) =2a(16) =-19391512143a(17) =2a(19) =2a(21) =2a(23) =2a(25) =2a(27) =2a(29) =2