Hi Wayne, welcome to the Board!
Calculating the number of possible permutations or combinations is straightfoward.
For permutations: =PERMUT(50,5). The answer is 254,251,200
For combinations: =COMBIN(50,5). The answer is 2,118,760
You're after unique combinations -- but where you do want to store over 2 million results, and how would you reference them?