To generalize, an object with $n$ bits (where $n$ is an integer) can hold $2^n$ (2 to the power of n, also commonly written 2^n) unique values. Therefore, with an $8$-bit byte, a byte-sized object can hold $2^8$ ($256$) different values. An object that uses $2$ bytes can hold $2^{16}$ ($65536$) different values!
When we say "To generalize" some thing into a mathematical formula, what does people actually mean ? Does it mean a particular behavior always repeat in a similar manner so that we come up with a equation to represent that behavior. So the equation being extract from the manual testing thousand of time till we found out behavior's pattern. How can we be so sure that the equation work for this time and it will always correct in the future. In another words, how do people come up with math equation ? Does it come from manual testing thousand of time ?