A permutation is, in combinatorics, a sequence formed from the elements of a finite set in which each element appears exactly once. The number of permutations is n factorial.
Number of permutations
$$P_{n}=n!=1\times2\times\dots\times(n-1)\times n$$
where,
Pn— number of permutations of n elements;
n!— n factorial.
See also:
Permutation FAQ
What is a permutation?
A permutation is an arrangement of distinct elements where the order matters.
What is the formula for the number of permutations?
The number of permutations of n distinct elements is Pn = n!, where n! is n factorial.
