Triangle, read by rows, where T(n,k) = C(n*(n-1)/2-k*(k-1)/2+n-k+1,n-k).

Terms

a(0) =1a(1) =2a(2) =1a(3) =6a(4) =3a(5) =1a(6) =35a(7) =15a(8) =4a(9) =1a(10) =330a(11) =120a(12) =28a(13) =5a(14) =1a(15) =4368a(16) =1365a(17) =286a(18) =45a(19) =6a(20) =1a(21) =74613a(22) =20349a(23) =3876a(24) =560a(25) =66a(26) =7a(27) =1a(28) =1560780a(29) =376740