A happy number is defined by the following process. Starting with any positive integer, replace the number by the sum of the squares of its digits, and repeat the process until the number equals 1 (where it will stay), or it loops endlessly in a cycle which does not include 1. Those numbers for which this process ends in 1 are happy numbers, while those that do not end in 1 are unhappy numbers (or sad numbers).
Read more about Happy Number: Overview, Sequence Behavior, Happy Primes, Special Happy Numbers, Happy Numbers in Other Bases, Cubing The Digits Rather Than Squaring, Origin, Popular Culture, Programming Example
Famous quotes containing the words happy and/or number:
“How happy a thing were a wedding,
And a bedding,
If a man might purchase a wife
For a twelvemonth and a day;”
—Thomas Flatman (1637–1688)
“If matrimony be really beneficial to society, the custom that ... married women alone are allowed any claim to place, is as useful a piece of policy as ever was invented.... The ridicule fixed on the appellation of old maid hath, I doubt not, frightened a very large number into the bonds of wedlock.”
—Sarah Fielding (1710–1768)