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

Terms

a(0) =1a(1) =1a(2) =3a(3) =11a(4) =45a(5) =199a(6) =925a(7) =4457a(8) =22059a(9) =111473a(10) =572759a(11) =2983137a(12) =15713985a(13) =83570601a(14) =448105431a(15) =2419865513a(16) =13149245161a(17) =71844158103a(18) =394456062591