( (13 ^2) + 1 = (7 ^2) + (11 ^2) & (17 ^2) + 1 = (11 ^2) + (13 ^2) & (23 ^2) + 1 = (13 ^2) + (19 ^2) & (31 ^2) + 1 = (11 ^2) + (29 ^2) ) ;