how long does the equation od pi go on?
π is not an "equation", it is an irrational number.
That is, it cannot be expressed accurately as a fraction.
The number π has been calculated with high-speed computers to several billion decimal places.
There is no pattern or repetition.
Here is a weird page that has π to 1 million decimal places, just in case your are interested.
http://newton.ex.ac.uk/research/qsystems/collabs/pi/pi6.txt