The first four terms are 3 / 5, 4 / 8, 5 / 11, 6 / 14 Then a general formula of the sequence is

The first four terms are 3 / 5, 4 / 8, 5 / 11, 6 / 14 Then a general formula of the sequence is

Molecule: n + 2
Denominator: 3N + 2