Triangle T(n,k) = n!/(k!*(n-3*k)!), for n >= 3*k >= 0, read by rows.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =6a(5) =1a(6) =24a(7) =1a(8) =60a(9) =1a(10) =120a(11) =360a(12) =1a(13) =210a(14) =2520a(15) =1a(16) =336a(17) =10080a(18) =1a(19) =504a(20) =30240a(21) =60480a(22) =1a(23) =720a(24) =75600a(25) =604800a(26) =1a(27) =990a(28) =166320a(29) =3326400