I assume that this is a sequence and you need to find the next number in the sequence.
The first two numbers are give as 133 and 142, we can get the difference between them by subtraction as follows:
142 - 133 = 9
This means that adding 9 will generate the next term as follows:
133
133+9 = 142
142 + 9 = 151
This means that : n=151
