The Collatz conjecture is a conjecture in mathematics that concerns a sequence defined as follows: start with any positive integer n.
Then each term is obtained from the previous term as follows: if the previous term is even, the next term is one half of the previous term.
If the previous term is odd, the next term is 3 times the previous term plus 1. The conjecture is that no matter what value of n, the sequence will always reach 1.