Doubly square dates
4 April 2001 was the first doubly square date of the century because whether written in the order day.month.year or in the order month.day.year (in each instance with two digits for each element) it comes out as 04.04.01, and 40401 is 2012.
Still with two digits for each element, there are some doubly square dates for which the square that comes from the order day.month.year is not the same as the square that comes from the order month.day.year. This is the case for each of the next two doubly square dates after 4 April…
