EQ pots and the S-curve formula?

[MetalGuy]

As you know some EQs call for an S-curve pot. This is how the curve of an actual  digital pot for EQs looks like:




My questions is which formula describes this curve and/or how to derive such formula from the resistors values shown in order to be able to calculate such values for a potentiometer  with any given value?

If I have a 50k pot can I just divide the shown resistors values in 2 and get the new ones?