bonanova Posted March 18, 2013 Report Share Posted March 18, 2013 Earlier this year I noticed that the date could be written as 1.13.13 [January 13, 2013] and the day and month multiplied gave the year [modulo 100] Thirteen being both prime and greater then the number of months, this is the only such date in 2013. What year this century contains the most such dates? Quote Link to comment Share on other sites More sharing options...
0 superprismatic Posted March 18, 2013 Report Share Posted March 18, 2013 There are two years which have the maximum number of three such dates: 2017 with dates 1/17/17, 7/31/17, 9/13/17 and 2019 with dates 1/19/19, 7/17/19, 11/29/19. If, however, we drop the prime and larger than 12 requirements for the year modulo 100, the year 2020 contains the most such dates, 2040 comes in close behind. The 13 such dates in 2020 are: 1/20/20, 2/10/20, 4/5/20, 4/30/20, 5/4/20, 5/24/20, 6/20/20, 8/15/20, 10/2/20, 10/12/20, 10/22/20, 11/20/20, 12/10/20. Quote Link to comment Share on other sites More sharing options...
0 bonanova Posted March 19, 2013 Author Report Share Posted March 19, 2013 What I tried to convey by modulo 100 simply was 2013 becomes 13, which then is the straight product of 1 and 13. Being prime and all that is not a requirement, just dates like 5/12/60. You've opened up a richer set of possibilities, which I will now go back and work through. Thanks. Quote Link to comment Share on other sites More sharing options...
0 nakulendu Posted March 19, 2013 Report Share Posted March 19, 2013 Year 2024. Has Seven instances when product of date and month is the year (modulo 100) 1.24.24 2.12.24 3.08.24 4.06.24 6.04.24 8.03.24 12.02.24 Quote Link to comment Share on other sites More sharing options...
Question
bonanova
Earlier this year I noticed that the date could be written as 1.13.13 [January 13, 2013] and
the day and month multiplied gave the year [modulo 100] Thirteen being both prime and
greater then the number of months, this is the only such date in 2013.
What year this century contains the most such dates?
Link to comment
Share on other sites
3 answers to this question
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.