Triangle read by rows: T(n,k)=k*binomial(n-2k,3k) (n>=5, 1<=k<=n/5).

Terms

a(0) =1a(1) =4a(2) =10a(3) =20a(4) =35a(5) =56a(6) =2a(7) =84a(8) =14a(9) =120a(10) =56a(11) =165a(12) =168a(13) =220a(14) =420a(15) =286a(16) =924a(17) =3a(18) =364a(19) =1848a(20) =30a(21) =455a(22) =3432a(23) =165a(24) =560a(25) =6006a(26) =660a(27) =680a(28) =10010a(29) =2145