How many arrangements of k items from n items when there are duplicate items
62175
A general formula for $n$ distinguishable arrangements of length $\ell$ of a sequence of a given size?
138732
How to replace multiple items with same count of a different item?
109264
Algorithm to separate items of the same type
137471
Permutations of a string with duplicate characters
29713
$k$ times's draw from $n$ numbers with replacement, each number at least appear once
45074
Combinatorics: Selecting objects arranged in a circle
134599
How do I do Combinatorics / Counting?
6432
How many ways can N elements be partitioned into subsets of size K?
101719
Finding the n-th lexicographic permutation of a string
57986
Sum of products of combinatorials
148703
Permutations with repeating digits
120095
How many ways to split n elements in k groups?
19101
Permutation induced by a partition
68581
Combination for subset with duplicates
60007
Partitions with at most k parts, each of at most l
155831
What are the total number of ordered permutations of a list of elements (possibly repeated)?
11876
Probability of complete coupon set in $K$ boxes where a box has $N$ distinct coupons?