I'm guessing that anybody that has dived into calendar math for any time at all can figure this one out. I don't want to give spoilers, so I will digress a bit, with apologies to Keith. A vaguely related curiosity is that given dates of the year fall on the seven days of the week with *almost* equal probability -- almost but not exactly equal. This is because the central postulate of the Gregorian calendar is that 400 years equals exactly 146,097 days. Unfortunately, this period in days is exactly divisible by seven, so the day-of-the-week pattern in our calendar repeats exactly every four centuries. Calendar math is full of weirdness like this. I *still* haven't wrapped my head around the Hebrew calendar. The Islamic calendar is far simpler in principle, and (intentionally) full of mystery in practice. On Sat, Jan 16, 2021 at 5:01 PM Keith F. Lynch <kfl@keithlynch.net> wrote:
There's a bit of Internet folklore that says September 1993 never ended. (Look up "Eternal September" for details.)
September 100, 1993 was otherwise known as Thursday, December 9th, 1993. September 1000, 1993 was otherwise known as Monday, May 27, 1996. September 10000, 1993 is today, otherwise known as Saturday, January 16, 2021.
I thought about the pattern of the days of the week of the successive rollover days, and concluded that there's just one day of the week that they will never land on. Can you see which one, and why?
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