Central column of triangle A065941.

Terms

a(0) =1a(1) =1a(2) =3a(3) =4a(4) =15a(5) =21a(6) =84a(7) =120a(8) =495a(9) =715a(10) =3003a(11) =4368a(12) =18564a(13) =27132a(14) =116280a(15) =170544a(16) =735471a(17) =1081575a(18) =4686825a(19) =6906900a(20) =30045015a(21) =44352165a(22) =193536720a(23) =286097760a(24) =1251677700a(25) =1852482996a(26) =8122425444a(27) =12033222880a(28) =52860229080a(29) =78378960360