[724Skinsfan]

For it not to be considered wrong everybody in the class would need to have the formulas stored in their calculator. Anybody that has them stored now has a competitive advantage over someone that doesn't. Most teachers are smart enough to realize this. I'll bet the professor didn't consider or simply forget to include the fact that you can't store the formulas. Maybe, his tests are geared so that the formulas are already provided. Who knows?

Follow your conscience, though. Like gibbsisgod (do we still call him giggity or was that somebody else?) said: the professor may have everyone clear their memory before the test starts.