G.f. A(x) satisfies A(x) = 1 + x*(1+x^2)^3*A(x)^3.

Terms

a(0) =1a(1) =1a(2) =3a(3) =15a(4) =73a(5) =384a(6) =2133a(7) =12280a(8) =72657a(9) =439140a(10) =2699656a(11) =16828512a(12) =106121637a(13) =675780934a(14) =4339520988a(15) =28068818814a(16) =182707928301