So first you need to see how much the numbers are going up in each time. From 6 to 11, it's going up 5, and from 11 to 16, it's going up 5, which means the first part of the expression will be 5n. Now, imagine the 5 multiplication table alongside the sequence, and see how to get from those values to the current values. So, from 5 to 6 you add 1, and from 10 to 11 you also add 1. This means your final answer is
5n + 1. I hope this helps!
