7. Definition: If $n$ different positive integers, for any two numbers among them, the product of these two numbers can be divided by the sum of these two numbers, then, this set of numbers is called an $n$-number Zu Chongzhi array.

For example: $60, 120, 180$ these three numbers form a three-number Zu Chongzhi array (since $(60 \times 120) \div (60 + 120), (60 \times 180) + (60 + 180), \quad (120 \times 180) + (120 + 180)$ are all integers). Please $\mathrm{E}_{5}$ provide a set of four numbers that form a Zu Chongzhi array.
$7.420,840,1260,1680$