Find an expression for the number of squares in the nth pattern of the sequence. i noticed that the number of squares you add in each pattern it depends on the pattern number (see image) but i don't know how to get the expression.

“exterior angles of triangles. an exterior (or external) angle is the angle between one side of a triangle and the extension of an adjacent side. try this drag the orange dots on any vertex to reshape the triangle.” look to get to the answer i explained what it means and other things i hope it you .