Sequence Identification Routines?

["Nick Jacobsen" <nick () ethicsdesign com>]

I was hoping one of you might have some input here...  I am black box
testing a web app that generates a 5 character (letter and number only,
lowercase) verification string, that it then emails to the email address on
file, and then the receiver has to type it in to continue with his
registration...  now, I am looking for some sort of programming routines,
snippets, or programs, that will look at a set of say, a 1000, numbers, and
tell me if there is any sensible pattern, off which to predict the next 5
character string in the sequence.  Any suggestions welcome!

Thanks,
Nick Jacobsen
Ethics Design
nick () ethicsdesign com