In mathematics
In number theory, an odious number is a non-negative number that has an odd number of 1s in its binary expansion.
The first odious numbers are:
1, 2, 4, 7, 8, 11, 13, 14, 16, 19, 21, 22, 25, 26, 28, 31, 32, 35, 37, 38 ...These numbers give the positions of the nonzero values in the Thue–Morse sequence.
Numbers that are not odious are called evil numbers.
References
Odious number Wikipedia(Text) CC BY-SA