You know how there's strings in pi (3.14)?? well how do you find the number you want?

Question

I know that their is strings like 0123456789, 333, 444, and so on.. but how are you supposed to know which position it is.. like a number like 102793.. how would you find that position?
Best answer = 10 points

Answer 1

Actually (sorry first poster), an algorithm which can calculate the nth digit of pi without knowing all the digits ahead of it was discovered recently. Here is the Wikipedia article about it:

http://en.wikipedia.org/wiki/Bailey-Borwein-Plouffe_formula

However, that isn't exactly your question. If you are looking for, say, the string "123456789", the first poster is correct that the only way to find it is to start with a really long decimal expansion and hope it is in there.

How many digits do you need? A nine-digit sequence would be one of one billion possible nine-digit sequences. If your pi expansion is one billion digits long, there is about a 63% chance you'll find it.

Answer 2

Pi doesn't follow any pattern. The only way to find sequences is to start calculating digits of pi and look through them (with a computer program, of course) until you eventually come across the one you want.

For each digit you add to the sequence you're looking for, the average number of digits you'll have to look through to find it will be 10 times greater.

Answer 3

The Nth digit of Pi is not directly calculatable (nor is any irrational number), so you must use a pre-calculated listing:
http://www.angio.net/pi/piquery