The fortnightly maths prize question for 26 September was:

5=2^{2}+1^{2} and 13=3^{2}+2^{2}

Make a good guess for a rule about which odd prime numbers can be broken down this way, into a sum of two squares. Make a good guess about which whole numbers generally (not just primes) can be broken down into a sum of two squares. Continue reading