Question 527436
<pre>
I'm not sure what you mean by "n(factor)k" 

I would answer "permutations", for the number of 4-letter 
"words" is P(26,4) or on

the TI-84, it's 

26 nPr 4 

And it is calculated by

26×25×24×23 = 358800

Maybe that's what you mean by n(factor)k.  I am not familiar with
"n(factor)k", but maybe you call that "26(factor)4".  I'm only familiar
with calling it "The number of permutations of 26 things taken 4 at
a time".

Regardless of what people call it, the number of 4-letter "words" 
without repeating letters is:

26×25×24×23 = 358800

Edwin</pre>