Looks like a fine Permutation to me.

WOw  Wow wOw wOW

It occurred to me as I started typing that Wowness  that my SO could actually calculate how many variations I could make with 3 letters and the ability to capitalize them or not.  You know my son could too.  That is the secret - they have a better memory.

So - using what memory I have left I GOOGLED it!

It is called a Permutation!

Say you have a certain number of things or objects. They can be numbers, letters, people, colors, etc. In how many different ways can these things be arranged in a row? A permutation of some number of objects means the collection of all possible arrangements of those objects.
Enter your objects (or the names of them), one per line in the box below, then click "Show me!" to see how many ways they can be arranged, and what those arrangements are.
Note: 8 items have a total of 40,320 different combinations. For the sake of output and server capacity, we cannot let you enter more than 8 items!

So I input W  w  O  o  W w

and the answer is:

Internal Server Error
 The server encountered an internal error or misconfiguration and was unable to complete your request.

Another thought:  The number of ways of obtaining an ordered subset of elements from a set of elements is given by

So