Number the years in each cycle starting with 0. For instance, the year 1096 CE is year 0, 1097 CE is year 1, 1098 CE is year 2, and so on. All years whose ordinal numbers are evenly divisible by 4 are leap years. The first year of each cycle (ordinal number 0) is a common ...
ISO weeks: Number of weeks according to ISO-8601 (weeks starting on Monday). The first week is the week with a Thursday in the new year (the first 4-day week). Leap years: Every year that is divisible by four is a leap year, except for years that are divisible by 100 but not by...