Answer:
4n+2
Step-by-step explanation:
The common difference between the terms is 4 which means that the sequence is an arithmetic sequence.
The general formula for arithmetic sequence is:

where a_n is the nth term, a_0 is the first term and d is the common difference between them.
We know that

Putting the value in general formula:

So the generalized pattern is 4n+2 ..
The answer to your problem is -2.1.