Numbers 249..250..251 are missing from Pokedex [duplicate]
Solution 1:
Your Pokedex will have entries only for Pokemon you have seen or caught. Within each region, any unseen entries, up to the highest numbered seen, are numbered; any entries beyond the highest numbered seen are missing. Pokemon numbered 249-251 are the legendary and mythic Pokemon at the end of the Johto Pokedex. If you haven't seen any of those, they are skipped and the next entry will be the first seen Pokemon in the Hoenn region.