Let T be the equilaterall triangle with sides = 1 length.

Let be the # of circles that can be packed tightly in n rows inside the triangle.

Let be the combined area of the circles. Find the limit of as n -> infinity.

I believe I have to find a series for the number of circles in the triangles, right? So I need to find something to represent 1, 3, 6, 10, 15 ... ?