27, 26, 37, 37
16.
11
27.
The next number will be 13+21 = 34
The next number is 27. Nice puzzle! The reason is on discussion page, for those who are still working on it.
The series 1 6 10 13 15 (1+5=6; 6+4=10, 10+3=13; 13+2=15) is completed by 15+1=16. The answer is 16.
37
35
22
17 cause it is the next prime number
37
37