Find the number n such that the following alphanumeric equation:
KYOTO
KYOTO
+ KYOTO
TOKYO
has a solution in the base-n number system.
(Each letter in the equation denotes a digit in this system, and different letters denote different digits)
Right to left. First digit on right implies (2*o) mod n = 0. This consequently implies only one of o=0 or o=n/2. Second obviously cannot hold because from middle digit k>o and thus k>n/2, but left digit yields 3k<=t<=n-1 which implies 3k