E.g.f. exp(exp(1/2*x^2+1/6*x^3)-1).

Terms

a(0) =1a(1) =0a(2) =1a(3) =1a(4) =6a(5) =20a(6) =95a(7) =525a(8) =2975a(9) =20300a(10) =143640a(11) =1131900a(12) =9548385a(13) =86096010a(14) =831475645a(15) =8488104625a(16) =91828436700