1,3 / 6,3 / 4,7 / 10,2 / 3,9 / 14,

1,3 / 6,3 / 4,7 / 10,2 / 3,9 / 14,

Note that there are fractions and integers, which are generally reduced to fractions, and then note that the denominators of items 2, 4, and 6 are 6, 10, and 14
So the above changes are: 4 / 4, 3 / 6, 6 / 8, 7 / 10, 8 / 12, 9 / 14
This should be the landlord copied a wrong number, the second item should be 5 / 6
Then the general formula can be (n + 3) / (2n + 2)