G.f. A(x) satisfies 2*(1-x) = Sum_{n=-oo..+oo} (x - A(x)^n)^(n+1) * (A(x) - x^n)^(n+1).

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =4a(5) =8a(6) =13a(7) =35a(8) =86a(9) =191a(10) =447a(11) =1103a(12) =2810a(13) =6974a(14) =17471a(15) =44795a(16) =115279a(17) =296474a(18) =763834a(19) =1981967a(20) =5164628a(21) =13473784a(22) =35236723a(23) =92443470a(24) =243157407a(25) =640688394a(26) =1691077318a(27) =4472493065a(28) =11849608512a(29) =31441695581