Using for loop to create an off diagonal elements

I only need to get the output to show an off diagonal elements like this,

formula to get off diagonal:

nbr=3

Here is what I did.

a 3 by 3 output by using the 1d array and zeros (3by3)

To be fair i am not sure what i was doing here because i was just trying out everything and could not understand. Hopefully, someone can help me. I have attached the file.