28 (add on the Prime number 11)
27.
27, 26, 37, 37
17
The next number is 27. Nice puzzle! The reason is on discussion page, for those who are still working on it.
37 as each number is increasing by odd numbers like 3, 5, 7, 9
I think 37. But that is only if the third number is wrong.
This is a peculiar number sequence which follows the following rule: +7, -4, +8, -3, +9, -2... The next few functions would be +10, -1, +11, -0 And thus the next few numbers in the sequence would be 17+10=27, 27-1=26, and so on. The sequence in total goes 2, 9, 5, 13, 10, 19, 17, 27, 26, 37, 37.
33
This series is of the function f(x) = x2+1, starting with x=0.The next number in the series is 26. The number after that is 37.
456789
21
26.Add successive odd numbers to get the next number in the list:1+1=2, 2+3=5, 5+5=10, 10+7=17, 17+9=26. The number following 26 would be 37: 26+11=37.