Dates and Palindromes
Posted by Ó Maolchathaigh on January 2, 2010
I happened to notice that today’s date, in the standard US nomenclature, is a palindrome: 01022010, if reading as January 2nd, 2010. That is the way most of us speak of the date in English in this country. Of course, it is sometimes written another way, as the 2nd of January, 2010. Under that convention, today’s date is 02012010, not a palindrome at all, and confusing. Of course, under that secondary convention, the palindrome for this year would be the 01 of February, 2010, or 01022010, but that dating convention leads to far more numerous palindromes. I prefer to use the first convention, by which the last such palindrome date was October 2nd, 2001, and, which is more interesting, the one before that was August 31, 1380!
Of note are these: October 10, 1010 (not a palindrome), although January 1st, 1010 was; December 12, 1212 is an interesting repeating two-digit number also, but, again, not a palindrome; and November 11, 1111 (now, that was quite a date!). Perhaps people don’t consider 11111111 as a palindrome?
So, assuming today is the palindrome for 2010, then one question that would arise is: when is the next such year? Obviously, it occurs on November 2nd, 2011; 11022011. However, no such date palindrome occurs again until 2020: 02022020. For those who put a lot of faith into numbers, it may mean something. It means nothing of importance to me, but, still, I find it interesting to note that our 12-month, approximately 30-day cycles yield such rare sequences of numbers.
This would all be so much simpler is there was only one conventional way to write a date. So, I’m looking forward to February 2nd of 2020, the first date in 1010 years that is unambiguously a palindrome by any convention, even one that puts the year first.
Is the next dual-use, unambiguous one after the year 2020 in March of 3030? There is, of course, Sept. 22, 2290, an ambiguous palindrome (It’s either 09222290 or 22092290), and October 3rd, 3001, (it’s either 10033001 or 03103001). Another 1010 years? I leave that to you, but I believe there is such a date. Tell me if you think you know what it is. There’s a hint in this post.
institutrice said
The one after 02-02-2020 (which I think is so very cool) would be 12-02-2021. I had already done the next two after today when I was trying to figure out why the last one was so long ago on 08-31-1380. What can I say, I’m a true Math Geek. 😀
O'Maolchaithaigh said
Damn. I missed that one; I didn’t spend a lot of time on this. I got the one right after that.
O'Maolchaithaigh said
Actually, I was really going for the next unambiguous one, one that would apply to either dating convention.
O'Maolchaithaigh said
12/12/2121 -also unambiguous by any convention.