#86
Happy numbers
| Difficulty: | Medium |
| Topics: | math |
Happy numbers are positive integers that
follow a particular formula:
take each individual digit, square it,
and then sum the squares to get a new number.
Repeat with the new number and eventually,
you might get to a number whose squared sum is 1.
This is a happy number.
An unhappy number (or sad number) is one that loops endlessly.
Write a function that determines if a number is happy or not.
 | (= (__ 7) true) |
| (= (__ 986543210) true) |
| (= (__ 2) false) |
| (= (__ 3) false) |