G.f. satisfies: A(x) = 1/A(-x*A(x)^2).

Terms

a(0) =1a(1) =2a(2) =6a(3) =24a(4) =110a(5) =496a(6) =2156a(7) =9216a(8) =38742a(9) =160032a(10) =664532a(11) =2898848a(12) =13923468a(13) =75361600a(14) =450629592a(15) =2844358656a(16) =18224898790a(17) =116051632704a(18) =728724233988