HP Prime Graphing Wireless Calculator - Manual (Page 114)

110 Functions and commands
Combination The number of combinations (without regard to order) of n
things taken r at a time.
COMB(n,r)
Example: Suppose you want to know how many ways five
things can be combined two at a time.
COMB(5,2)
returns
10.
Permutation Number of permutations (with regard to order) of n things
taken r at a time: n!/(n–r)!.
PERM (n,r)
Example: Suppose you want to know how many permutations
there are for five things taken two at a time.
PERM(5,2)returns 20.
Random
Number Random number. With no argument, this function returns a
random number between zero and one. With one argument
a, it returns a random number between 0 and a. With two
arguments, a, and b, returns a random number between a
and b. With three arguments, n, a, and b, returns n random
number between a and b.
RANDOM
RANDOM(a)
RANDOM(a,b
RANDOM(n,a,b)
Integer Random integer. With no argument, this function returns either
0 or 1 randomly. With one integer argument a, it returns a
random integer between 0 and a. With two arguments, a,
and b, returns a random integer between a and b. With three
integer arguments, n, a, and b, returns n random integers
between a and b.
RANDINT
RANDINT(a)
RANDINT(a,b)
RANDINT(n,a,b)
Normal Random normal. Generates a random number from a normal
distribution.
RANDNORM( μ , σ )