A palindrome is a string whose reversal is identical to the string. For instance, the strings: POP, CIVIC, RADAR, and REVIVER are palindromes.
How many different strings over uppercase alphabet (A to Z) of length 9 are not palindromes?

Question

A palindrome is a string whose reversal is identical to the string. For instance, the strings: POP, CIVIC, RADAR, and REVIVER are palindromes.
How many different strings over uppercase alphabet (A to Z) of length 9 are not palindromes?

unklerhaukus · Answer

every nine character palindrome is definable by the first 5 characters

unklerhaukus · Answer

how many different, 5 character strings are there?