phangorn (version 2.1.1)

dfactorial: Arithmetic Operators

Description

double factorial function

Usage

dfactorial(x)
ldfactorial(x)

Arguments

x

a numeric scalar or vector

Value

dfactorial(x) returns the double factorial, that is $x\!\! = 1 * 3 * 5 * \ldots * x $ and ldfactorial(x) is the natural logarithm of it.

See Also

factorial, howmanytrees

Examples

dfactorial(1:10)