Number reasoning questions 1,3,4,6,11,19, ()

Number reasoning questions 1,3,4,6,11,19, ()

1,3,4,6,11,19,(28)
3-1 + 2 = 44-3 + 5 = 66-4 + 9 = 1111-6 + 14 = 192,5,9,14. The difference between two adjacent numbers is 3,4,5. Since 14 + 6 = 20, it can be inferred that the next number is 2019-11 + 20 = 28