Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Is there any pattern in this (e.g. Once per five years)?
Is it a sliding window?

share|cite|improve this question
1  
It's more complicated than that due to leap years among other things. Check out J.H. Conway's Doomsday rule where all your questions should be answered in full detail. – t.b. Apr 16 '11 at 8:09
    
@Theo Buehler Thanks. Post as an answer and I will accept. I thought it wouldn't be so simple. – basarat Apr 16 '11 at 8:20
up vote 4 down vote accepted

Mostly, in cycles of 6, 11, and 11 years. Leap years only repeat every 28 years. See http://wiki.answers.com/Q/How_often_in_years_do_calendars_repeat_with_the_same_day-date_combinations

share|cite|improve this answer
    
+1 thank you very much. Just what I was looking for – basarat Apr 17 '11 at 6:05

All depends on the year it starts first birthday after you been born. If your birthday starts on same day , same date, same month. It will take 5 years, 6 years or 11 years which will bring you to your original day of birthday and the sequence never change. Sequence (11 6 5 6 11 6 5 6 11) all depends on which years sequence(5 6 11 6 5 6 11 6 5)or(6 5 6 11 6 5 6 11 6) you start your sequence, but it never change.You can test it yourself and see the consistency of the sequence birthday, same day of the week.

share|cite|improve this answer

I found out: It is a sequence like this every 11-6-5-6-11 years (periodic), 11-6-5-11 years.

Dio Stavroulias

share|cite|improve this answer

It's more complicated than that due to leap years among other things. Check out J.H. Conway's doomsday rule where all your questions should be answered in full detail.

See also the answer and the comments to this related question.

share|cite|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.