3x-1
3x+1 recreated in Python
If a number is odd it is multiplied by 3 and 1 is added to the product. If a number is even it is divided by 2.
These rules are applied directly to any positive natural number. All numbers till 2 to the power 62 have been found and all end up at 1.
Since 1 is odd multiplying by 3 and adding 1 becomes 4, dividing by 2 gives 2, and dividing again gives 1, which creates a loop.
This Python code uses Matplotlib to show the graph of any number inputed.