# FACTDOUBLE

## Content

This function calculates the double factorial of the specified number.

## Syntax

`FACTDOUBLE(number)`

## Arguments

The argument can be any non-negative numeric value.

## Remarks

The *number* argument must be a non-negative number. If you provide a number that is not an integer for the *number* argument, the decimal portion of the number is ignored. 
The double factorial is calculated as follows for even numbers:

`n!! = n(n-2)(n-4) ... (4)(2)`

The double factorial is calculated as follows for odd numbers:

`n!! = n(n-2)(n-4) ... (3)(1)`

## Data Types

Accepts numeric data. Returns numeric data.

## Examples

`FACTDOUBLE(E3)`

`FACTDOUBLE(R3C5)`

`FACTDOUBLE(6)` gives the result 48