happy number

Given a base b integer


where d1 is the least significant digit and dk is the most significant, and the function


if computing f(n) and iterating that function on the result eventuallyMathworldPlanetmath leads to a fixed pointPlanetmathPlanetmath of 1, then n is said to be a happy number in base b.

For b=2 and b=4, all numbers are happy numbers. All standard positional bases have happy numbers.

Title happy number
Canonical name HappyNumber
Date of creation 2013-03-22 16:19:56
Last modified on 2013-03-22 16:19:56
Owner PrimeFan (13766)
Last modified by PrimeFan (13766)
Numerical id 4
Author PrimeFan (13766)
Entry type Definition
Classification msc 11A63