[seqfan] Super-birthday

[Eric Angelini]

Hello SeqFans,
[sorry if this is known]

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]

Best,
É.