The difference between five and eight is three.

The difference between 8 and 17 is 9.

17 and 44 differ by 27.

Did you get a look at him?

They are 1, 3, 9 and 27 respectively.

The number in the back is three times that in the front.

The fifth difference is 27*3=8 1.

This sequence should appear next.

44+8 1= 125