Formula for permutations and combinations

Question

Suppose there are $27$ possible letters $\{A, B,... ,Z\}$ and they can be arranged in any order including spaces, capitalization, order.

Is the formula

$P(n,r) = n!(n−r)!$

still correct?

Answer 1

If the number of spaces make a word unique, then I can have infinite permutations.

If not, then it is essentially an extra character. Also, capitalisation would add another 26 characters to your set. Then you can permute over 26+26+1 characters using the standard formula.

(You might have to remove some permutations which have a leading or trailing whitespace; if you don't consider those unique.)