164062

I think every time there is a number you add a rectangle and every to rectangles added you add two. This is because with 2 rectangles you only have 3 add one you then have 4 but add another one and you get 5. This is because adding another one makes you also have medium sized rectangles inside the biggest one made out of the smallest ones. Therefore every other number you add two. I think this would work on any amount of rectangles.