August 5, 2014
We have a simple little problem today: Given an integer n > 2, find the minimum b > 1 for which n base b is a palindrome. For instance, n = 15 = 11112 = 1203 = 334 = 305 = 236 = 217 = 178 = 169 = 1510 = 1411 = 1312 = 1213 = 1114; of those, bases 2, 4 and 14 form palindromes, and the least of those is 2, so the correct answer is 2.
Your task is to write a program that calculates the smallest base for which a number n is a palindrome. When you are finished, you are welcome to read or run a suggested solution, or to post your own solution or discuss the exercise in the comments below.