<image>The mathematical problem is as follows:

As shown in figure (1), there is an equilateral triangle. Figure (2) is a shape obtained by connecting the midpoints of each side of figure (1). Figure (3) is a shape obtained by connecting the midpoints of the three sides of the smaller triangle in figure (2), and so on. What is the analytical expression of the function \(y\) of the number of triangles in figure (n) with respect to \(n\)?
