Just doing a quick google search that appears to be the equation for the NACA 4 series airfoils. Which are not good for transonic use (i.e. aircraft propellers).

I did another search and found a document that uses equations to obtain the ordinates for the 6A series. However, looking over it, I don't think its worth the effort to go that route. I already have the points I need. This wouldn't justify the effort to code.