Find the wrong number from the following series ? 37 47 52 67 87 112 142

The given series follows the rule,
+(5x1), +(5x2), +(5x3), +(5x4), +(5x5),....

So starting from 37, 37 + 5 = 42, 42 + 10 = 52, 52 + 15 = 67, 67 + 20 = 87,...
So wrong number is 47 which is to be 42.