Formula to Calculate Exponential Curves?

Im messing around in HTML5 Canvas which uses Javascript to draw to the Canvas.  The Canvas is being used to display an RPG Character attribute over the number of levels.  Making a Linear Slope (straight line) is easy.  (NOTE: same post on a couple places I dont visit regularly, varied responses are VERY helpful...)

Im curious what the formula is to calculate the value for each level that implements an Exponential Curve?

The following image is from the Editor that I am trying to emulate.  This is a Non Exponential Curve, which I already have working.

These are the Exponential Curves that I want to emulate, and I dont know the value of the Slider when its set to either "Fast" or "Slow", and "Middle" is a Non Exponential Curve (so guessing a value of 0 there.

What would I need to do to generate a curve that looks like this, where we input the Level 1 and Level 99 values?  Experimented with something like this but its not coming out anywhere like I need it to...

let exp_list = [null];
let pow = parseInt(slider.value);
for (let i = 1; i < 99; i++){
  exp_list[i] = 500 * (n ** pow) + 1; // ???? ab^x
}

Not quite sure what this formula is to plug in here.  Halp?