nth term formula

Find the nth term formula, 50th term and 100th term for the following sequences:

1.  3, 7, 11, 15.....

2.  -1, 4, 9, 14, 19....

3. 6, 9, 12,15..........

4. 7, 12, 17, 22..........

5. 8, 11, 14, 17.........

6. 11, 17, 23, 29..........

7. 13, 15, 17, 19, 21..........

8. 3, 8, 13, 18..........

9. 4, 13, 22, 31.........

10. 6, 10, 14, 18.........