Pi, the Magic Number of Circles

π (pronounced pi) is the ratio between a circle's circumference and its diameter. The circle is one of the most fundamental shapes, so how come its defining number is so odd? It's irrational and it's transcendental, which means there is no simple way of expressing π, other than giving it a cute name. What do the decimals of this mysterious number look like? Are there repetitive sequences among the decimals? If I look for a sequence in π, will I find it?

I think π is a fascinating number and I'd like people to join me. The app that I wrote and chose to call "Pi, the Magic Number of circles" lets you search for number strings in the first million decimals of π. When I first searched in π, the string I searched for was my birthday 580923 (Swedish date format). The second was my wife's birthday, then those of my children: they were all in π.

Today is May 5 2011, i.e. 110505, which is in π at position 205044 :-). And just before 110505, you have 525850 and just after you have 111853. Incidentally, turning today's date around, writing 050511, you find that it's there too at 205046. It seems today is a special day, Pi-wise !!

That's how I use this app.

Lots of people bought it!