# FACTDOUBLE

Formulas / FACTDOUBLE
Calculate the double factorial of a number.
=FACTDOUBLE(number)
• number - The value for which to return the double factorial

## Examples

• =FACTDOUBLE(6)

The FACTDOUBLE function calculates the double factorial of a number. The double factorial is defined as the product of all integers from 1 up to the number, but counting in increments of 2. For example,the function returns 48. This is because 6*4*2*1 = 48.

• =FACTDOUBLE(7)

The FACTDOUBLE function can be used to calculate odd double factorials as well. This example returns 105. This is because 7*5*3*1 = 105.

## Summary

The FACTDOUBLE function calculates the double factorial of a number, which is the product of all the integers from 1 up to the given number, in steps of two.

• The FACTDOUBLE function takes one argument, which should be a positive integer.
• The argument is written as number, and the output of the function is written as !!.

What is the FACTDOUBLE function?
The FACTDOUBLE function returns the double factorial of a number.
What error does the FACTDOUBLE function return when the number argument is not an integer?
The FACTDOUBLE function returns the #VALUE! error if the number argument is not an integer.
What error does the FACTDOUBLE function return when the number argument is negative?
The FACTDOUBLE function returns the #NUM! error if the number argument is negative.
What error does the FACTDOUBLE function return when the number argument is odd?
The FACTDOUBLE function returns the #NUM! error if the number argument is odd.