The eban numbers in English (OEIS sequence A006933) are all even (a theorem by N. J. A. Sloane). The eban numbers in Bulgarian (BG ebans) are even and odd. I am a theorem-finder too:
The number of the even BG ebans equals the number of the odd BG ebans.
This is due to the fact that a number can be BG eban only if it ends with 0 or 3.