Permutations with Repetitions - Arrangements of elements
Combinations with Repetitions - Swapping elements based on different amounts of repetition
Combinations                  - Actual elements involved

7r7 7r6 7r5r2 7r4r3 7r5 7r4r2 7r3r3 7r3r2r2 7r4 7r2r2r2 7r3r2 7r3   7r2r2   7r2   7r1
1!   2!              3!        3!/2! 3!/2!   4!/3!       4!/2! 5!/4! 5!/3!2! 6!/5! 7!/7!
7C1  7C2             7C3                     7C4               7C5           7C6   7C7