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:
“A happy marriage perhaps represents the ideal of human relationship—a setting in which each partner, while acknowledging the need of the other, feels free to be what he or she by nature is: a relationship in which instinct as well as intellect can find expression; in which giving and taking are equal; in which each accepts the other, and I confronts Thou.”
—Anthony Storr (b. 1920)
“How often should a woman be pregnant? Continually, or hardly ever? Or must there be a certain number of pregnancy anniversaries established by fashion? What do you, at the age of forty-three, have to say on the subject? Is it a fact that the laws of nature, or of the country, or of propriety, have ordained this time of life for sterility?”
—Philip Dormer Stanhope, 4th Earl Chesterfield (1694–1773)