This calculator can be used to generate all types of permutations from n to m elements with repetitions.
You can read about permutations from n to m here - Combinatorics. Combinations, arrangements and permutations.
The elements can be repeated in such type of permutations. Permutations with repetitions are also called finite sets. Two permutations with repetition are equal only when the same elements are at the same locations.
For example: permutations with repetitions of the three elements A, B, C by two are - AA, AB, AC, BA, BB, BC, CA, CB, CC.
The number of possible permutations with repetition of n elements by m equals
You can check generation algorithm here