FACTDOUBLE

Returns the double factorial of the specified number.

Syntax

FACTDOUBLE( Integer x ) → Number

Parameters

x

Required. The number to calculate double factorial of. Must be non-negative.

Remarks

The double factorial of a number is the product of every other integer numbers from 1 to the number itself. That is, if x is even, the double factorial of x is 2*4*6*…*x; if x is odd, the double factorial is 1*3*5*…*x. The double factorial of zero is, by definition, 1.

If x is not integer, it is automatically truncated. If x is less than zero, the function returns the #NUM! error value.

Example

Formula

=FACTDOUBLE(0)
=FACTDOUBLE(5)

See Also

Function Reference
FACT Function