a(n) = Product_{k|n} k!.

Terms

a(0) =1a(1) =2a(2) =6a(3) =48a(4) =120a(5) =8640a(6) =5040a(7) =1935360a(8) =2177280a(9) =870912000a(10) =39916800a(12) =6227020800