New Post: combinations

I don't understand it:

In the last example we have 5 element set. We create all possible combinations,

output is:

        31
        A
        B
        C
        D
        E
        E
        A B
        A C
        A D
        A E
        B C
        B D
        B E
        C D
        C E
        D E
        D E
        A B C
        A B D
        A B E
        A C D
        A C E
        A D E
        B C D
        B C E
        B D E
        C D E
        C D E
        A B C D
        A B C E
        A B D E
        A C D E
        B C D E
        B C D E
        A B C D E
        */

I think there should be exactly 32 combinations (as 2^5=32).
Some of combinations are duplicated, for example:

B C D E
B C D E