Triangle of C(n+1,k)*C(2*n-3*k,n-3*k)/(n+1) by rows.

Terms

a(0) =1a(1) =1a(2) =2a(3) =5a(4) =1a(5) =14a(6) =5a(7) =42a(8) =21a(9) =132a(10) =84a(11) =3a(12) =429a(13) =330a(14) =28a(15) =1430a(16) =1287a(17) =180a(18) =4862a(19) =5005a(20) =990a(21) =12a(22) =16796a(23) =19448a(24) =5005a(25) =165a(26) =58786a(27) =75582a(28) =24024a(29) =1430