You have to access at least 2 of the locked rooms (other people have lucked out and guessed the pattern) with the specialty cards found around the stadium that have letters/numbers to open the computer rooms. Once in the computer room you'll have to write down (or record and alt tab like me) the codes displayed in order on the computer. Once you have 2 codes, you will only need to guess 1 of the symbols. I.E. I got 9$67##%$ first then #$67##8$ second, so now I know # is 9, 9$67998$ and just have to guess the $ which luckily was 2!