Add 2, add 5. First term: 12.

To find what each term is being added by, you can subtract the previous term from the current term.

In this case, we have the first term as 12. To find the second term, we can add 2 to the first term:
12 + 2 = 14

To find the third term, we can add 5 to the second term:
14 + 5 = 19

So the sequence is: 12, 14, 19.