In this sequence there are actually two sequences. 1 sequence for the numerators and one sequence for the denominators. The following transformation applies to the sequence for the denominators : -9
This creates the following sequence: [-4, -13, -22, -31, -40]
The following transformation applies to the sequence for the numerators: -6
This creates the following sequence: [9, 3, -3, -9, -15]
Take a good look at how to rewrite the fractions in the series to recognize the pattern.
For example, 22/3 can be rewritten as -22/-3