# FACTDOUBLE

Returns the double factorial of a number.

If this function is not available, and returns the #NAME? error, install and load the Analysis ToolPak add-in.

2. In the Add-Ins available list, select the Analysis ToolPak box, and then click OK.
3. If necessary, follow the instructions in the setup program.

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:

Example

The example may be easier to understand if you copy it to a blank worksheet.

1. Create a blank workbook or worksheet.
2. Select the example in the Help topic.

Note   Do not select the row or column headers.

Selecting an example from Help
1. Press CTRL+C.
2. In the worksheet, select cell A1, and press CTRL+V.
3. To switch between viewing the results and viewing the formulas that return the results, press CTRL+` (grave accent), or on the Formulas tab, in the Formula Auditing group, click the Show Formulas button.
A B
Formula Description (Result)
=FACTDOUBLE(6) Double factorial of 6 (48)
=FACTDOUBLE(7) Double factorial of 7 (105)

Applies to:
Excel 2003