![On the number of permutations supported in SAS software](https://blogs.sas.com/content/iml/files/2015/03/t_maxperm.png)
There's "big," and then there is "factorial big." If you have k items, the number of permutations is "k factorial," which is written as k!. The factorial function gets big fast. For example, the value of k! for several values of k is shown in the following table. You can