FACTDOUBLE (double factorial)

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FACTDOUBLE (double factorial)

Syntax:

FACTDOUBLE(Number)

Description:

This returns the double factorial of a Number.

The double factorial is calculated as follows:

If Number is even, its double factorial is 2*4*6*...*Number.

If Number is odd, its double factorial is 1*3*5*...*Number.

The given number must be ≥ 0. Decimal places are automatically truncated.

Example:

FACTDOUBLE(10) equals 2*4*6*8*10, which is 3840

FACTDOUBLE(11) equals 1*3*5*7*9*11, which is 10395

See also:

FACT