Multifactorial Calculator
Calculator Use
Calculate the following factorials. Note that n!!, and similarly to other multifactorials, is not the same as (n!)!. Refer to formulas below.
- factorial n!
- double factorial n!!
- triple factorial n!!!
- quadrupal factorial n!!!!
- quintuple factorial n!!!!!
Factorial Formula
n! = n × (n - 1) × (n - 2) × (n - 3) × ... × 1
Factorial of 5
5! = 5 × 4 × 3 × 2 × 1 = 120
Double Factorial Formula
n!! = n × (n - 2) × (n - 4) × (n - 6) × ...
Double Factorial of 10
10!! = 10 × 8 × 6 × 4 × 2 = 3,840
Note that some programming languages use the function dfactorial to compute double factorials.
Triple Factorial Formula
n!!! = n × (n - 3) × (n - 6) × (n - 9) × ...
Triple Factorial of 22
22!!! = 22 × 19 × 16 × 13 × 10 × 7 × 4 × 1 = 24,344,320
References
[1] For more information on double, triple and quadruple factorials please see the Multifactorial page at Wolfram MathWorld.