My employer uses alphanumeric 2 factor codes and I'm so certain that they have a bias towards some letters (mostly y and z). I know I'm probably wrong and it's probably because they appear so rarely in real words, but I can't shake the feeling they aren't random.

Only problem is that I don't have the algorithm. I started writing down all codes I got but since I only get 5 a week, it's a long process. I'll probably switch jobs before I have valid results.

Not that it would change anything, but I'd be really curious how biases in those codes could appear.