Triangle T(n,m) = Sum_{i=0..n-m} C(2*m-1,n-i-1)*C(n-i-1,i)*C(n-i-1,n-m-i)/(2*m-1).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =3a(5) =2a(6) =0a(7) =5a(8) =10a(9) =5a(10) =0a(11) =5a(12) =26a(13) =35a(14) =14a(15) =0a(16) =3a(17) =44a(18) =125a(19) =126a(20) =42a(21) =0a(22) =1a(23) =52a(24) =295a(25) =574a(26) =462a(27) =132a(28) =0a(29) =0