Expansion of e.g.f. exp(arcsin(tanh(x))).

Terms

a(0) =1a(1) =1a(2) =1a(3) =0a(4) =-3a(5) =-4a(6) =21a(7) =80a(8) =-263a(9) =-2224a(10) =4841a(11) =88960a(12) =-99723a(13) =-4942144a(14) =-199939a(15) =366928640a(16) =501445617a(17) =-35219691264a(18) =-101818966319