If you want to play more with it and try to found when all 7 digit combination of pi repeat themself, I build a Pi as a service API for pi day. It can serve the first 1 billions digit of pi over http.<p><a href="http://piaas.org/" rel="nofollow">http://piaas.org/</a>
Just a random question that popped into my head while reading (thank you for the article!)... What would be the longest repetitions of digits within various orders of magnitude of Pi?<p>In other words, the first 10 characters (again looking at only the fractional portion:<p>1415926535<p>The longest repetition is a length of one and the digit is 1.<p>Playing with regexes, I found:<p>In 100 digits, you get a repetition of the digits 592<p>In 1000 digits, the first longest repetition is 23846<p>In 10000 digits, I found a six digit repetition, 120190 but
at that point, the quadradic nature of the regex made searching for 7 impossible so I would probably write a program that used something like suffix trees to get further.
There is this service to search in the digits: <a href="http://www.angio.net/pi/piquery" rel="nofollow">http://www.angio.net/pi/piquery</a>
There's no proof that pi contains every possible number combinations. It's a common misconception that somewhere in pi you'll find everything.
One of the other articles referenced, about De Bruijn sequences, is much more interesting <a href="http://www.datagenetics.com/blog/october22013/index.html" rel="nofollow">http://www.datagenetics.com/blog/october22013/index.html</a>