text: I think it's 9 and 11.\n\nIf you take every second number, eg. 7, 3, 13 and 19, you can see that to get from 7 to 3 you minus 4, to get from 3 to 13 you add 10 and to get from 13 to 19 you add four therefore the for the next number you minus 10. So 19 minus 10 equals 9.\nFor the numbers 11, 8, 15 and 18, you minus 3 from 11 to get 8, you add 7 to 8 to get 15 then you add 3 to get 18. For the next one you would have to minus 7. So 18 minus 7 equals 11.\n\nThe sequence would be: 7, 11, 3, 8, 13, 15, 19, 18, 9, 11