Find the term which does not fit into the series: 1CC, 5FU, 9IT, 15LS, 17OR

Explanation:-

1st letter :1 + 4 5 + 4 9 + 4 13 + 4 17
2nd letter :C + 3 F + 3 I + 3 L + O
3rd letter :V - 1 U - 1 T - 1 S - 1 R
Thus, the term 15LS is wrong and must be replaced by 13LS.