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

Terms

a(0) =1a(1) =1a(2) =1a(3) =3a(4) =6a(5) =17a(6) =42a(7) =120a(8) =330a(9) =962a(10) =2797a(11) =8334a(12) =24989a(13) =75905a(14) =232142a(15) =715830a(16) =2220473a(17) =6928411a(18) =21723883a(19) =68424327a(20) =216376757a(21) =686742855a(22) =2186771571a(23) =6984248840a(24) =22368127861a(25) =71818903891a(26) =231132440916a(27) =745454242656