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 : +2
This creates the following sequence: [-3, -1, 1, 3, 5, 7, 9]
The following transformation applies to the sequence for the numerators: +4
This creates the following sequence: [11, 15, 19, 23, 27, 31, 35]