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 : -1
This creates the following sequence: [1, 0, -1, -2, -3]
The following transformation applies to the sequence for the numerators: +2
This creates the following sequence: [7, 9, 11, 13, 15]
Take a good look at how to rewrite the fractions in the series to recognize the pattern.
For example, 0/1 can be rewritten as 0/9