SOLUTION: Find a formula of the number of permutations of the set {1,2,3,,,,n} where none of the numbers are in their natural position if you could help me again please

Algebra.Com
Question 984076: Find a formula of the number of permutations of the set {1,2,3,,,,n} where none of the numbers are in their natural position if you could help me again please
Answer by Edwin McCravy(20054)   (Show Source): You can put this solution on YOUR website!
The formula for the number of "derangements", or the ways a given 
n-permutation can be rearranged so that every element moves to a new 
position is called n-subfactorial, and is denoted by !n, the 
exclamation mark is before the number instead of after it like 
a regular factorial.

The formula is

,
where  e = 2.718281828459045235360287471352662497757247093699959574966967...

Edwin
RELATED QUESTIONS

Find a formula of the number of permutations of the set {1,2,3,,,,n} where exactly k... (answered by Edwin McCravy)
Use the formula: s=n^2+n all over 2 1. where S is the sum of the first (answered by stanbon)
Given the following set designations: U = {x | x € N and x < 15} and N is the set of... (answered by stanbon)
what is the formula to find x digits of a natural number? Example: how many 2 digit... (answered by JoelSchwartz)
Find all ordered pairs (m, n) of natural numbers that satisfy the equation 9" + 3 - 2 = (answered by ikleyn)
n>k+s+2 . How many permutations has the set {1,2,3...n} ,with condition that in the... (answered by Edwin McCravy)
If n is the set of natural numbers that are factors of 16, what is the set in roster... (answered by Edwin McCravy)
the formula S= n(n+1)over 2 can be used to find the sum of the first n natural numbers... (answered by gonzo)
Determine whether the statement is true or false. If the statement is false, give a... (answered by solver91311)