Suppose we have a number n; if it is even divide by 2. If it is odd, multiply by 3 and add 1. Do all numbers lead to 1 if they follow this sequence? If true, prove why.
That is called the "Collatz's Conjecture" and it is not for you or me, but for top-notch mathematicians to prove or disprove! Good luck !
O I didn't know that. Thanks for letting me know!