Calculation of possible combinations without repetition
This function calculates the number of possible combinations from a set without repetition. When combining without repeating, a number k is selected from the total n.

The number of possible combinations from a set without repetition is calculated. In the case of combinations without repetition, a number k is selected from the total n.
The order of the selected objects is ignored. Each object may only be selected once in the object group, i.e. without repetition. For the urn model, this corresponds to a noreplacement, noorder draw.
The formula is:
\(\displaystyle \frac{n!}{(nk)! · k!}\)
This example shows how many groups with 2 objects from the digits 1 to 3 can be formed. They are the groups (1,2), (1,3) and (2,3). So three groups.
