Triangle T(n,k) = C(n+k-1,k)*C(2*n-1,n-k).

Terms

a(0) =1a(1) =1a(2) =1a(3) =3a(4) =6a(5) =3a(6) =10a(7) =30a(8) =30a(9) =10a(10) =35a(11) =140a(12) =210a(13) =140a(14) =35a(15) =126a(16) =630a(17) =1260a(18) =1260a(19) =630a(20) =126a(21) =462a(22) =2772a(23) =6930a(24) =9240a(25) =6930a(26) =2772a(27) =462a(28) =1716a(29) =12012