# [seqfan] Re: superbirthdays

Robert Munafo mrob27 at gmail.com
Mon Jan 17 01:54:38 CET 2011

```Yeah, I guess I'll relent on this one -- if only because those sequences
work for the *Julian* (not Gregorian calendar) and there are some (Orthodox
Christians and some people in Egypt I believe) who still use that calendar,
and there is also the Coptic calendar which has the same pattern and has
been in continuous use since Ptolemy! :-)

- Robert

On Sun, Jan 16, 2011 at 19:41, Maximilian Hasler <
maximilian.hasler at gmail.com> wrote:

> yes I agree, that's why I hesitated to submit this.
> but well, since it is by chance valid from 1900 to 2100 it does have
> some relevance for those who live now.
> Of course the comment about the validity is necessary,
> and for other obvious reasons it does not even make much sense to give
> 200/28 x 4 terms (the average human will not have more than 15
> super-birthday parties...)
>
> Maximilian
>
> On Sat, Jan 15, 2011 at 10:33 PM, Robert Munafo <mrob27 at gmail.com> wrote:
> > There are more than 4 patterns, depending on how old you are in a year
> (like
> > 1900 or 2100) that is a multiple of 100 without also being a multiple of
> > 400.
> >
> > The ages 28, 56 and 84 (if you are lucky) have worked for everyone who
> has
> > lived in recent memory but soon will no longer apply to newly born
> people.
> >
> >> >On Thu, Jan 13, 2011 at 9:30 AM, Eric Angelini <Eric.Angelini at kntv.be>
> >> wrote:
> >> >>
> >> >> I was born on Wednesday, September 12, 1951.
> >> >> My next "Wednesday, September 12" birthday
> >> >> (or super-birthday) was in 1956 together with
> >> >> my (ordinary) 5th birthday. Due to leap years,
> >> >> my personal sequence of super-birthdays is:
> >> >> S = 0,5,11,22,28,33,39,50,56,...
> >> >> Is it true that only 4 different such sequences
> >> >> exist (depending if you are born one year before
> >> >> a leap year, a leap year, one year after a leap
> >> >> year, two years after a leap year)?
> >> >> Is it true that, whatever their birth year is,
> >> >> all humans have a super-birthday which matches
> >> >> their regular 28th birthday?
> >> >>
> >> >> [This comes from a nice little book by
> >> >>  Alexandre Moatti: http://goo.gl/vB9r6]
> >
>
--
Robert Munafo  --  mrob.com