Mohamed decided to track the number of leaves on the tree in his backyard each year. The first year, there were 500500500 leaves. Each year thereafter, the number of leaves was 40\%40%40, percent more than the year before. Let f(n)f(n)f, left parenthesis, n, right parenthesis be the number of leaves on the tree in Mohamed's back yard in the n^\text{th}n th n, start superscript, start text, t, h, end text, end superscript year since he started tracking it. fff is a sequence. What kind of sequence is it?