a(n) = A327005(n, n).

Terms

a(0) =1a(1) =0a(2) =1a(3) =2a(4) =6a(5) =24a(6) =105a(7) =510a(8) =2765a(9) =16408a(10) =105210a(11) =724580a(12) =5330149a(13) =41649828a(14) =344120777a(15) =2995027126a(16) =27368953170a(17) =261825429024