Four number-pairs have been given, out of which three are alike in some manner and one is different. Select the one that is different.

17 : 291 15 : 227 13 : 169 11 : 123

13 : 169

The logic is : (Ist number)2 + 2  = second number 17 : 291 - (17)2 + 2 = 291 15 : 227 - (15)2 + 2 = 227 13 : 169 - (13)2 = 169 (odd) 11 : 123 - (11)2 + 2 = 123