2n! / number of divisors of n.

Terms

a(0) =2a(1) =2a(2) =6a(3) =16a(4) =120a(5) =360a(6) =5040a(7) =20160a(8) =241920a(9) =1814400a(10) =39916800a(11) =159667200a(12) =6227020800a(13) =43589145600a(14) =653837184000