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:
“And happy lines! on which, with starry light,
Those lamping eyes will deign sometimes to look,”
—Edmund Spenser (1552?–1599)
“... in every State there are more women who can read and write than the whole number of illiterate male voters; more white women who can read and write than all Negro voters; more American women who can read and write than all foreign voters.”
—National Woman Suffrage Association. As quoted in History of Woman Suffrage, vol. 4, ch. 13, by Susan B. Anthony and Ida Husted Harper (1902)