Collatz problem
2 is the only even prime number. Moreover, prime numbers are fractal . Collatz problem is divided by two parts which are even and odd numbers. When you have odd numbers, you put them in 3n+1. Then you always have even numbers, so you divide them by 2. You repeat it over and over again, until you get 1. At first, you have odd numbers (3-29). You put them in 3n+1. You see (10,16,22・・・,88). You divide them by 2 such as (5,8,11・・,44). Half of them are odd numbers which are yellow. The others are even numbers, so you keep dividing them by 2 such as (4,7,10,13,16,19,22). Green numbers are odd which is 50%. This is fractal. You see 1 in the end. Ex. ●17-52-26-13-40-20-10-5-16-8-4-2-1 ●25-76-38-19-58-29-88-44-22-11-34-17-52-26-13-40-20-10-5-16-8-4-2-1 ●65-196-98-49-148-74-37-112-56-28-14-7-22-11-34-17-52-26-13-40-20-10-5-16-8-4-2-1 This is expansion and still fractal. Ex. ●133-400-200-100-50-25-76-38-19-58-29-88-44-22-11-34-17-52-26-13-40-20-10-5-16-8-4-2-1