G.f. satisfies A(x) = 1 + x*A(x) / (1 - x^2*A(x)^5).

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =8a(5) =30a(6) =103a(7) =368a(8) =1407a(9) =5531a(10) =21905a(11) =87689a(12) =355929a(13) =1461022a(14) =6046160a(15) =25194331a(16) =105661615a(17) =445692621a(18) =1889454880a(19) =8045796200a(20) =34398989998a(21) =147606568810a(22) =635481458969