skuddårsekvens
A skuddårsekvens, or leap year sequence, refers to the recurring pattern of years that are designated as leap years within the Gregorian calendar system. A leap year is a year containing an extra day, February 29th, which is added to keep the calendar year synchronized with the astronomical year. The skuddårsekvens is governed by specific rules to ensure this synchronization.
The primary rule for a skuddårsekvens is that a year is a leap year if it is
This skuddårsekvens creates a cycle of 400 years. Within this 400-year cycle, there are exactly 97 leap