dCode is free and its tools are a valuable help in games, puzzles and problems to solve every day! You have a problem, an idea for a project, a specific need and dCode can not (yet) help you? You need custom development? Contact-me!

This page is using the new English version of dCode, please make comments !

Tool for computing factorials. Factorial n! is the product of all integers numbers (not zero) inferior or equal to n.

Answers to Questions

How to calculate a factorial?

Factorial of a number \( n \) is calculated with a simple multiplication: it is the product of the positive integers numbers (not null) less or equal to \( n \).

The usual notation to indicate a factorial is the exclamation mark positioned after the number. The factorial of \( n \) is noted \( n! \).

Note that the factorial of zero is equal to one : \( 0! = 1 \)

Example: Here are the values of the first factorials $$ 0! = 1 \\ 1! = 1 \\ 2! = 2 \\ 3! = 6 \\ 4! = 24 \\ 5! = 120 \\ 6! = 720 \\ 7! = 5040 \\ 8! = 40320 \\ 9! = 362880 \\ 10! = 3628800 $$

What is the Gamma Function?

Euler-Gamma is an extension of the factorial function over the Complex numbers. dCode offers calculation over the Reals. $$ \forall\,n \in \mathbb{N}, \; \Gamma(n+1)=n! $$

How to calculate a negative factorial?

You have to use the Gamma function.

How to quickly compute a factorial value?

For large numbers, it is possible to estimate the value of \( n! \) with a good precision using the Stirling formula. $$ n!\sim\sqrt{2\pi n}\left(\frac{n}{e}\right)^n $$

Ask a new question

Source code

dCode retains ownership of the source code of the script Factorial. Except explicit open source licence (indicated Creative Commons / free), any algorithm, applet, snippet, software (converter, solver, encryption / decryption, encoding / decoding, ciphering / deciphering, translator), or any function (convert, solve, decrypt, encrypt, decipher, cipher, decode, code, translate) written in any informatic langauge (PHP, Java, C#, Python, Javascript, etc.) which dCode owns rights can be transferred after sales quote. So if you need to download the Factorial script for offline use, for you, your company or association, see you on contact page !

dCode uses cookies to customize the site content, analyze user behavior and adapt dCode to your use. Some data is stored and collected for advertising purposes and may be shared with our partners. OK