I don't see the jump in logic, either.
Your opponent's odds of having a pocket pair should be the same 1/17 that you have.
I have no idea where he gets the 16 to 6 figure. There are 16 ways to have any given non-pair and 6 ways to have any given pair, but there are 78 non-pair rank combinations and only 13 pair ranks.
If that's how he's calculating it, it's ...
I suggest you two option :
Online with this
On pc,(best in my opinion) Equilab is a free software
where do you able to save your range.
Keep in mind : many poker room, like pokerstars, don't accept equilab running on pc while pokerstars running too.