Today is 4/9/16 (in places that put the month first) which means three perfect squares in a row: 22, 32, 42. Last time that happened was January 4th, seven years ago, and next will not be until 2025, in September on the 16th. After that we have to wait for a new century again because we don’t have enough months to make it work for 16/25/36.
For everyone who lives everywhere else, the first and second dates this century would be 1 April 09 and 4 September 16 instead, and the third one wouldn’t happen for the same reason there won’t be a 16/25/36 on our calendar. Not enough months to write 9.[16th month].25.
The moral of the story is that we get one extra perfect square series by naming our days with month first and day second. Not sure it’s worth the confusion created by numbering differently from how everyone else does, but that’s for another time.
Here it is without all my nattering:
1/4/09 (January 4th), 4/9/16 (April 9th), 9/16/25 (September 16th)
1.4.09 (April 1st), 4.9.16 (September 4th), –.–.– (9th day of 16th month in 25th year)
If you like really big perfect squares, you can smash the days, months, and years together. I’m going to work on having more capacity for conceiving of these giant ones. In the meantime, fortunately, someone else posted about that.