Friday, February 11, 2011

Palindrome dates!

One of my friends reminded me of speciality of today's date i.e. 11-02-2011 (British and Indian date format). It is a palindrome! I started digging more into it and wondered how common are these palindrome dates. In the format considered here, we could see that there were none starting from 12th century to 19th century!! And in this century i.e. 2001 to 2100, these palindrome dates would only occur only on 28 days in the months of February (in various years like 2001,2002, 2010, 2011, 2012, 2020, 2021, 2022, 2030, 2031, 2032, etc). In the next century, these palindrome dates will occur for 31 days in the months of December (in various years).

For this century the probability of a day having a palindrome date is 28/(36500) = 7.67e-4.

Conclusion: Palindrome dates are not very common!!