Problem:

The positive integers, x, y, and z, are consecutive terms of an arithmetic progression. Given that n is a positive integer, the equation, x2 [−] y2 [−] z2 = n, has exactly one solution when n = 20:

132 [−] 102 [−] 72 = 20

In fact there are twenty-five values of n below one hundred for which the equation has a unique solution.

How many values of n less than fifty million have exactly one solution?

872187

Code:The solution may include methods that will be found here: Library.java .

public interface EulerSolution{public String run();}
/*  * Solution to Project Euler problem 36 * By Nayuki Minase *  * http://nayuki.eigenstate.org/page/project-euler-solutions * https://github.com/nayuki/Project-Euler-solutions */public final class p036 implements EulerSolution {		public static void main(String[] args) {		System.out.println(new p036().run());	}			public String run() {		int sum = 0;		for (int i = 1; i < 1000000; i++) {			if (Library.isPalindrome(Integer.toString(i, 10)) && Library.isPalindrome(Integer.toString(i, 2)))				sum += i;		}		return Integer.toString(sum);	}	}