-2X=(- 1) times the square of (-1) times the square of 2.

4X=(- 1) times the cube of (-1) times the square of 2.

. . . . . .

therefore

The nth data is: (-1) times the nth power of (-1) times the nth power of X.

You can understand it by reading and writing it down. The key is that there are not so many mathematical symbols on the Internet.