StatGen5

y = -0.0016*(x-6)^4+0.0623*(x-6)^3-0.6272*(x-6)^2+3.302*(x-6)-6.697

That is the extrapolation of the Pathfinder Point buy system which typically only accommodates scores between 7 and 18. This generator allows you to go as low as 3 and high as 20 with any given stat. In addition to being able to create a character within the bounds of a Low, Standard, High, or Epic Fantasy you may also generate a random stat array via three different methods:

4d6 Drop the Lowest
(Averages out to a 18.5 Point Buy)
5d4+1d6 Drop the Two Lowest
(Averages out to a 25.7 Point Buy)
3d6 Twice, Keep the Better Set
(Averages out to a 17.2 Point Buy)

And dont think this system only works for Pathfinder, My playgroup uses this system for our 5th Edition D&D Sessions and we love it. A nice mix of min/max for the players that enjoy that, and a whole lot of ability to flavor characters how you want. Some of the best stories come from the Rogue that has the Charisma of a Robot Shield Guardian or the Bear Totem Barbarian who has the intelligence of an actual Owlbear.

Let the adventure begin...