Expansion of e.g.f. exp(arctanh(arctanh(x))).

Terms

a(0) =1a(1) =1a(2) =1a(3) =5a(4) =17a(5) =129a(6) =769a(7) =7797a(8) =66849a(9) =848481a(10) =9506241a(11) =145041093a(12) =2007271089a(13) =35799178401a(14) =589807203777