Triangle read by rows: T(n,k) = binomial(t(n) - t(k-1),k), where t(j) = j*(j+1)/2; 1<=k<=n.

Terms

a(0) =1a(1) =3a(2) =1a(3) =6a(4) =10a(5) =1a(6) =10a(7) =36a(8) =35a(9) =1a(10) =15a(11) =91a(12) =220a(13) =126a(14) =1a(15) =21a(16) =190a(17) =816a(18) =1365a(19) =462a(20) =1a(21) =28a(22) =351a(23) =2300a(24) =7315a(25) =8568a(26) =1716a(27) =1a(28) =36a(29) =595