Circular r-Permutation of n Elements

INTRODUCTION

This equation computes the number of circular ordered arrangements of r distinct elements for a set of n elements. For example, the number of ways to arrange 5 children in a circle choosing from a group of n children.

SPECIAL CASE

The special case where n = r is the number of circular permutations of any set of n elements.  See Circular Permutations for an example of this special case involving dead chickens.

author: GerryPerham

Combinatorics Calculators

• `n!` - factorial
• `n!  sqrt(2 pi n) (n/e)^n` - Stirling's factorial approximation
• `{::}_nC_k` - combinations
• `C_r(n,k)` - combinations with repetitions
• `{::}_nP_k` - permutations
• `P_r(n)` - permutations with repetitions
• `P_(comp)(n,2)` - Comparison permutations
• `P_c (n,r)` - Circular r-Permutations of n Elements