ID EN
…
#Math

FACTDOUBLE

Excel Functions

Get double factorial of a number

Syntax

EXCEL 
=FACTDOUBLE(number)

Arguments

Parameter Description
number A number greater than or equal to -1.

Return Value

Calculated double factorial

Details

The FACTDOUBLE function returns the double factorial of a number. A double factorial is calculated differently for even and odd numbers. For an even number, n, it's the product of all even integers less than or equal to n and greater than or equal to 2. For an odd number, the double factorial is the product of all odd integers less than or equal to n and greater than or equal to 1. The double factorial for both zero and -1 are defined as 1. For numbers less than -1, a double factorial is not defined. FACTDOUBLE takes just one argument, number, which should be a positive integer. If number is not an integer, the decimal portion of number will be removed before the factorial is calculated. For even numbers, the double factorial is the product of all even integers less than or equal to number

Examples

Examples

For even numbers, the double factorial is the product of all even integers less than or equal to number and greater than or equal to 2. For example, t

EXCEL 
=FACTDOUBLE(8)
=8*6*4*2
=384
Examples

For odd numbers, the double factorial is the product of all odd integers less than or equal to number and greater than or equal to 1. The double facto

EXCEL 
=FACTDOUBLE(7)
=7*5*3*1
=105
Examples

The double factorial for zero and -1 are defined as 1:

EXCEL 
=FACTDOUBLE(0) // returns 1
=FACTDOUBLE(-1) // returns 1

See Also

FACT