This calculator can be used to generate all types of permutations from n to m elements without repetitions.
You can read about permutations from n to m here - Combinatorics. Combinations, arrangements and permutations.
The elements can not be repeated in such type of permutations. Two permutations with repetition are equal only when the same elements are at the same locations.
For example: permutations without repetitions of the three elements A, B, C by two are - AB, AC, BA, BC, CA, CB.
The number of possible permutations without repetition of n elements by m equals
You can check the generation algorithm here