Triangle, read by rows, T(n,k)=k/n*Sum_{i=0..n-k} C(2*n,n-k-i)*C(2*n+i-1,i).

Terms

a(0) =1a(1) =4a(2) =1a(3) =24a(4) =8a(5) =1a(6) =172a(7) =64a(8) =12a(9) =1a(10) =1360a(11) =536a(12) =120a(13) =16a(14) =1a(15) =11444a(16) =4672a(17) =1156a(18) =192a(19) =20a(20) =1a(21) =100520a(22) =42024a(23) =11088a(24) =2096a(25) =280a(26) =24a(27) =1a(28) =911068a(29) =387456