Triangle: T(n,k)=C(4n,2k), 0<=k<=n.

Terms

a(0) =1a(1) =1a(2) =6a(3) =1a(4) =28a(5) =70a(6) =1a(7) =66a(8) =495a(9) =924a(10) =1a(11) =120a(12) =1820a(13) =8008a(14) =12870a(15) =1a(16) =190a(17) =4845a(18) =38760a(19) =125970a(20) =184756a(21) =1a(22) =276a(23) =10626a(24) =134596a(25) =735471a(26) =1961256a(27) =2704156a(28) =1a(29) =378