I actually don't know. They say in the paper they can't figure out a better way to approximate Solomonoff induction in the UTM (universal Turing machine) sectio

I actually don't know. They say in the paper they can't figure out a better way to approximate Solomonoff induction in the UTM (universal Turing machine) section, so they just guess some reasonable value (based on knowledge of the program that generates the sequence).