FACTDOUBLE

Returns the double factorial of a number.

If this function is not available, run the Setup program to install the Analysis ToolPak. After you install the Analysis ToolPak, you must enable it by using the Add-Ins command on the Tools menu.

Syntax

FACTDOUBLE(number)

Number   is the value for which to return the double factorial. If number is not an integer, it is truncated.

Remarks

• If number is nonnumeric, FACTDOUBLE returns the #VALUE! error value.
• If number is negative, FACTDOUBLE returns the #NUM! error value.
• If number is even:

  

• If number is odd:

  

Examples

FACTDOUBLE(6) equals 48

FACTDOUBLE(7) equals 105