I have 5 categories - A, B, C, D & E.
I want to basically create groups that reflect every single combination of these categories without there being duplicates.
So groups would look like this:
- A
- B
- C
- D
- E
- A, B
- A, C
- A, D
- A, E
- B, C
- B, D
- B, E
- C, D . . . etc.
This sounds like something I would use the binomial coefficient $n \choose r$ for, but I am quite fuzzy on calculus and can't remember exactly how to do this.
Any help would be appreciated.
Thanks.