G.f. satisfies: A(x) = 1 + x/A(-x*A(x)^4)^2.

Terms

a(0) =1a(1) =1a(2) =2a(3) =7a(4) =26a(5) =123a(6) =622a(7) =3490a(8) =20468a(9) =125643a(10) =792606a(11) =5118050a(12) =33612998a(13) =223770400a(14) =1505528080a(15) =10213807498a(16) =69746716716a(17) =478693572991