On factorial If (2n)! = 2x4x6x Why not just write (2n)!, these two are not the same? Or n!

On factorial If (2n)! = 2x4x6x Why not just write (2n)!, these two are not the same? Or n!

(2n)! Is the multiplication of even numbers from 1 to 2n
(2n)! Is the multiplication of all numbers from 1 to 2n
The two are different!