An odious number is a nonnegative number that has an odd number of 1s in its binary expansion. The first few odious numbers are therefore 1, 2, 4, 7, 8, 11, 13, 14, 16, 19, ... (OEIS A000069). Numbers that are not odious are said to be evil numbers.
Odious Number
See also
Economical Number, Evil Number, Happy Number, Lucky Number, Unhappy Number, Wasteful NumberExplore with Wolfram|Alpha
References
Sloane, N. J. A. Sequence A000069 in "The On-Line Encyclopedia of Integer Sequences."Referenced on Wolfram|Alpha
Odious NumberCite this as:
Weisstein, Eric W. "Odious Number." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/OdiousNumber.html