A Double Century

When will the beginning of a century fall on a Sunday? (Note to pedants: for this question, I define the centuries as beginning with the year ending in 00, not 01.)



To help you in your quest…



There are no agreed-upon leap year rules with timescales longer than 400 years, so what we have is one fixed pattern that repeats itself exactly every 400 years. No, I'm not telling you what the pattern is.... look it up on wikipedia at your peril!



Now keep in mind that a fair amount of tinkering with the calendar occurs now and again. Our current (Modern Gregorian) calendar was instituted on Friday, 15 October 1582, and took a couple hundred years to be generally adopted. Prior to this, the year 1100 had started on a Sunday, but timekeeping was so generally screwed up back then that when the Gregorian system was adopted, a bunch of days had to be removed to get the dates to synch up correctly with the seasons. (In the U.S., the missing days were September 3 through 13, 1752.)



Next question…There is already talk (premature in my opinion) that to get the current calendar to remain accurate, we'll need to eliminate one extra leap day every 4,000 years. Bearing this in mind, and the extra leap day is eliminated, when will the beginning of a Century then fall on a Sunday?

- Karl Sharman