Hello!

Here is this series 5,10,17,26...., the pattern is addition. The addition of consecutive odd numbers throughout the series starting with '5'. Look at the pattern for this series below:

5

10 = 5+5 (previous no.+ odd no 5)

17 = 10+7 (previous no.+next consecutive odd no after 5)

26 = 17+9

37 = 26+11

50 = 37+13

Final series is : 5,10,17,26,37,50

I hope this helps