Symmetric triangle of certain normalized products of decreasing factorials.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =1a(7) =2a(8) =2a(9) =1a(10) =1a(11) =6a(12) =12a(13) =6a(14) =1a(15) =1a(16) =24a(17) =144a(18) =144a(19) =24a(20) =1a(21) =1a(22) =120a(23) =2880a(24) =8640a(25) =2880a(26) =120a(27) =1a(28) =1a(29) =720