Finding book ISBN numbers in Pi

Geoff wrote a program to search Pi to find ISBN numbers. The first three books are Licentiate seminar on environmental engineering and biotechnology, Sneeuwwitje en Rozerood, and The Healing Knife.

Pi is an interesting number. It goes on forever, doesn't repeat itself, and appears to be entirely random. And in an infinite, random sequence, you get every possible combination of numbers eventually. Your phone number is in there somewhere. And every book written, if you convert the numbers into ASCII.

Searching Pi for books like that would be stupid though, you'll burn up the best computers on the planet before you get anything worthwhile. There is, however, a quicker alternative.

Almost every single book published since 1966 has an ISBN number. These days they all start 978, then there's another ten digits. The last one's a check digit made by multiplying the others up in a certain way.