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

Terms

a(0) =1a(1) =1a(2) =3a(3) =11a(4) =47a(5) =221a(6) =1117a(7) =5981a(8) =33619a(9) =197139a(10) =1200551a(11) =7567125a(12) =49233845a(13) =329945065a(14) =2273469967a(15) =16082532495a(16) =116649264071a(17) =866551528737