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Permutations and Combinations: In how many ways can we divide n distinct objects into r distinct groups of equal or unequal sizes having at least 1 object each?
What's the formula for dividing n distinct objects into r distinct groups of unequal sizes?
To divide n distinct objects into r distinct groups of unequal sizes, we will have to use the formula for Stirling numbers of the second kind. It is denoted by S(n,r) and represents the number of ways to partition n distinct objects into r non-empty sets.