The calendar can repeat at five or six year intervals, but does not always do so. The only simple pattern is that it repeats every 28 years. It repeats every 28 years as 28 is the lowest common multiple of the 4 year cycle of leap years and the 7 weekdays. So it is possible the calendar did repeat a couple of times, but then maybe not.This may be classed as useless info, but it is interesting.
The calendar can repeat at five or six year intervals, but does not always do so. The only simple pattern is that it repeats every 28 years. It repeats every 28 years as 28 is the lowest common multiple of the 4 year cycle of leap years and the 7 weekdays. So it is possible the calendar did repeat a couple of times, but then maybe not.This may be classed as useless info, but it is interesting.