G.f. satisfies 1 = Sum_{n>=0} x^n * (1 + x*A(x)^n)^n / A(x)^(n+1).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =3a(5) =7a(6) =19a(7) =59a(8) =193a(9) =668a(10) =2425a(11) =9163a(12) =35926a(13) =145658a(14) =609100a(15) =2621984a(16) =11600620a(17) =52686006a(18) =245365437a(19) =1170679945a(20) =5717651100a(21) =28564900769a(22) =145877374325a(23) =761035255393