What formula did Derren Brown memorize to calculate the roulette?

I want to know so I can try and memorize it too! Did he actually memorize one or was it some kind of trickery? Does such a formula exist? Where can I find it? Thanks!
Yes, yes I did. I meant I want to know what method he used to calculate where it would land. The formula.
He said about timing, and I get that bit, but he went into no more detail.