Singapore Math: How many squares can you find ?

This video shows how to visually identify the squares in a given figure and also come up with a formula to find the number of squares that can be found in a perfect square figure made of multiple smaller squares.

[samerkaradsheh]

How do you represent that as a formula?
(N)^2+(n-1)!^2?

[nilamsharma]

Thanks I knew this tricky questions but I had forget it your vedio made me remind thanks a lot~_-