kStatistics (version 2.0)

ff: Falling factorial

Description

Computes the descending (falling) factorial of a positive integer n with respect to a positive integer k less or equal to n.

Usage

ff( n, k )

Arguments

n

integer

k

integer

Value

integer

descending factorial

Details

ff(n, k) returns n(n-1)(n-2).....(n-k+1).

See Also

mkmSet, umSet, countP, nStirling2, intPart, mCoeff

Examples

# NOT RUN {
# Return 6*5*4 = 120
ff(6,3) 
# }