Expansion of (1+x)c(x^2)/((1-x^2*c(x^2))sqrt(1-4x^2)), c(x) the g.f. of A000108.

Terms

a(0) =1a(1) =1a(2) =4a(3) =4a(4) =15a(5) =15a(6) =56a(7) =56a(8) =210a(9) =210a(10) =792a(11) =792a(12) =3003a(13) =3003a(14) =11440a(15) =11440a(16) =43758a(17) =43758a(18) =167960a(19) =167960a(20) =646646a(21) =646646a(22) =2496144a(23) =2496144a(24) =9657700a(25) =9657700a(26) =37442160a(27) =37442160a(28) =145422675a(29) =145422675