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

Terms

a(0) =1a(1) =1a(2) =3a(3) =9a(4) =30a(5) =97a(6) =336a(7) =1153a(8) =4081a(9) =14552a(10) =52609a(11) =191657a(12) =704385a(13) =2604476a(14) =9687433a(15) =36207241a(16) =135920489a(17) =512182805a(18) =1936656361a(19) =7345211322a(20) =27935373368a(21) =106509551719a(22) =407015199144