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

Terms

a(0) =1a(1) =1a(2) =1a(3) =3a(4) =9a(5) =25a(6) =71a(7) =219a(8) =689a(9) =2189a(10) =7059a(11) =23091a(12) =76331a(13) =254489a(14) =855057a(15) =2892611a(16) =9843695a(17) =33674049a(18) =115735093a(19) =399448699a(20) =1383893277a(21) =4811005765a(22) =16777546935a(23) =58676543307a(24) =205751099671a(25) =723221934973