Multinomial

Multinomial[n1, n2, ...] gives the multinomial coefficient (n1+n2+...)! / (n1! n2! ...).

Examples

Multinomial coefficient:

Multinomial[2, 3, 4]
(* 1260 *)

Equivalent to binomial for two arguments:

Multinomial[3, 2]
(* 10 - same as Binomial[5, 3] *)

Counting permutations with repetition:

Multinomial[2, 2, 2]
(* 90 - ways to arrange AABBCC *)

Please visit the official Wolfram Language Reference for more details.