G.f. satisfies A(x) = 1 + x^4 + x*A(x)^4.

Terms

a(0) =1a(1) =1a(2) =4a(3) =22a(4) =141a(5) =973a(6) =7112a(7) =54040a(8) =422552a(9) =3377770a(10) =27478568a(11) =226753828a(12) =1893462584a(13) =15969598554a(14) =135842638632