T(n,k) = binomial(n,2*k)*binomial(2*k,k) for 0 <= k <= n, triangle read by rows.

Terms

a(0) =1a(1) =1a(2) =0a(3) =1a(4) =2a(5) =0a(6) =1a(7) =6a(8) =0a(9) =0a(10) =1a(11) =12a(12) =6a(13) =0a(14) =0a(15) =1a(16) =20a(17) =30a(18) =0a(19) =0a(20) =0a(21) =1a(22) =30a(23) =90a(24) =20a(25) =0a(26) =0a(27) =0a(28) =1a(29) =42