Oh look, it's basically the same problem I solved in my old node, Predict Random Numbers. Fifteen years ago. Back then, there wasn't so much information available online, so I actually had to get on my bike and ride to the Stanford math department library to find that algorithm.
That problem involves 48-bit numbers, which really aren't all that big. Maybe try something in the Number Theory category.
Update: Haha, we didn't have youtube back then either.