>Could you send it to me too, please?

I saw the algorithm for calculating the Serbian Orthodox Church Easter (they still use Gregorian calendar internally), but it's based on actual phases of the moon and is not sure to fire right each year, because the priests use their own sideric tables, which were not updated for centuries, and are probably few days in error, compared with the actual moon phases. Thus the actual date of Easter simply has to depend on whatever they print in their calendar. They do include moon phases with the days when they come, but I haven't really checked whether they have it right or not. Easter is on a Sunday, anyway, so it won't hurt your calendar either way.

The Orthodox and other Easter may differ by anything between zero and five weeks, even though the Gregorian calendar is off by only 13 days now.