Petals Around the Rose: Fraternity Register

interesting puzzle =p at first I thought it would relate somehow to Fibonacci's Sequence, since the number of petals on a flower is always a fibonacci number. That proved wrong after the first 10 seconds. Then after 5 min of guessing, I started getting the correct answer intuitively w/out knowing why, until finally entertaining the idea that the solution was more "outside the box". Total time: 10 min.