An unhappy number is a positive integer that is not a happy number. Starting from an unhappy number,
repeatedly replacing the current value by the sum of the
squares of the digits
in its decimal expansion never reaches 1.
The first few unhappy numbers are 2, 3, 4, 5, 6, 8, 9, 11, 12, 14, 15, 16, 17, 18,
20, ... (OEIS A031177).
See also
Economical Number,
Evil Number,
Happy Number,
Lucky
Number,
Odious Number,
Wasteful
Number
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References
Sloane, N. J. A. Sequence A031177 in "The On-Line Encyclopedia of Integer Sequences."Referenced
on Wolfram|Alpha
Unhappy Number
Cite this as:
Weisstein, Eric W. "Unhappy Number." From
MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/UnhappyNumber.html
Subject classifications
