Triangle read by rows: T(n,k)=k*binomial(n-2k,3k+1) (n>=6, 0<=k<=(n-1)/5).

Terms

a(0) =1a(1) =5a(2) =15a(3) =35a(4) =70a(5) =126a(6) =2a(7) =210a(8) =16a(9) =330a(10) =72a(11) =495a(12) =240a(13) =715a(14) =660a(15) =1001a(16) =1584a(17) =3a(18) =1365a(19) =3432a(20) =33a(21) =1820a(22) =6864a(23) =198a(24) =2380a(25) =12870a(26) =858a(27) =3060a(28) =22880a(29) =3003