Consider the construction of a string of characters which is C characters in length, by randomly selecting from an N-character alphabet (selecting randomly with replacement).

If the probability that all characters are distinct equals the probability that exactly one character appears twice but all the other characters appear just once, then what is the number of characters in the alphabet?

Find N in terms of C.

(In reply to re: Seems to be this by Brian Smith)

I made a mistake in my algebra when I did this, and recognized an impossible answer.

Posted by Charlie on 2025-04-09 08:21:17