For integers n ³ 0, n factorial (written n!) is defined by
- 0! = 1
- n! = (n) * (n-1) * (n-2) * ... * (3) * (2) * (1)
Who created the factorial?
The factorial notation of n! was first used by Christian Kramp in 1808 as a convenience to the printer. Kramp also did work on relating the factorial to non-integers; usually, the factorial is used only with non-negative integers. To learn more about how certain mathematical symbols were introduced into the field, check out Jeff Miller's webpage on the subject.
Interesting Factorial Facts
- 10! = 3,628,800, which is the number of seconds in six weeks!
- 11! is larger than the number of seconds in a year!
- 12! exceeds the number of seconds in 12 years!
- 13! surpasses the number of seconds in a century!
- n! is one of the fastest growing functions - it grows faster than any of the polynomial functions or the exponential functions!