2603 has the prime factors 19 x 137 which further decompose into (102 – 92) x (42 + 112). Therefore the rubric states: ‘puzzle NUMBER is BRACKET TEN SQUARED MINUS NINE SQUARED BRACKET TIMES BRACKET FOUR SQUARED PLUS ELEVEN SQUARED BRACKET’.

First prize John Bennett, Havant, Hants
Runners-up Julie Sanders, Bishops Waltham, Southampton; Richard Andrews, Ashford, Middlesex