a(n) = A027144(2n, n-1).

Terms

a(0) =1a(1) =8a(2) =30a(3) =224a(4) =880a(5) =6656a(6) =27104a(7) =206336a(8) =859392a(9) =6565888a(10) =27765760a(11) =212615168a(12) =908943360a(13) =6970998784a(14) =30045757440a(15) =230691307520