MathDB

Let

n

be an integer greater than

3

. A square of side length

n

is divided by lines parallel to each side into

n^2

squares of length

1

. Find the number of convex trapezoids which have vertices among the vertices of the

n^2

squares of side length

1

, have side lengths less than or equal

3

and have area equal to

2

Note: Parallelograms are trapezoids.

1