The rising factorial has the following formula
Note that the number of ways of arranging
n objects in
m ordered boxes is
![[m]^n](/images/eqns/52b43ab1d34eb4b554d4503a567d1851.gif)
. (Here, the ordering in
each box matters). Thus, 2 objects in 2 boxes have the following 6 possible arrangements:
Moreover, the number of non-decreasing maps from a set of
n to a set of
m ordered elements is
![[m]^n / n!](/images/eqns/01fb53ea27d5450564cc640babc32e57.gif)
.
Thus the set of nondecreasing maps from

to

is the 20 elements:
Example:
#include <codecogs/maths/discrete/combinatorics/arithmetic/rising_factorial.h>
#include <iostream>
int main()
{
std::cout << Maths::Combinatorics::Arithmetic::rising_factorial(5, 3) << std::endl;
return 0;
}Output:
210
References:
SUBSET, a C++ library of combinatorial routines,
http://www.csit.fsu.edu/~burkardt/cpp_src/subset/subset.htmlParameters
| x | the first rising factorial argument |
| n | the second falling factorial argument |
Returns
- the rising factorial of the pair of values x and n
Authors
- Lucian Bentea (August 2005)
Source Code
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