G.f. satisfies A(x) = exp( Sum_{n>=1} 2^n*A(x^n)*x^n/n ).

Terms

a(0) =1a(1) =2a(2) =8a(3) =32a(4) =140a(5) =624a(6) =2928a(7) =14048a(8) =69200a(9) =347040a(10) =1768120a(11) =9122144a(12) =47572128a(13) =250341312a(14) =1327718272a(15) =7089595552a(16) =38082093120a(17) =205638343552