For mathematically minded people, this is probably an easy one. Unfortunately, I am not one of those, and therefore I am too dumb to even know how to do an effective google search or searching already asked questions here. So, I am sorry if this was answered already.
My problem is: I have three variables; A,B,C. I want to know how many combinations of these exist when order does not matter, and I ignore single variables. So in the case of A,B,C there are 4 combinations: A:B, A:C, B:C and A:B:C.
How can I generalize that to n variables? I am looking for a formula where I can input the number of variables and get the number of combinations.