The next two terms would be 37 and 49.
The rule being applied in this quadratic sequence is to add by every corresponding even number, beginning at 9.
When we are at 9, we add 4 to get 13. The next even number after 4 is 6, so we add 6 to get 19. The next even number after 6 is 8, so we add 8 to get 27. The process continues as so and the answers are received accordingly.
