Not new question

[SeryZone]

How works Fractal eXtreme's acceleration???

I have 4096-colors palette. FX have 228.
Formula coloring:
Index = iteration/(4096/228)/SPEED

If we set color mapping: Speed - 1.000, Acceleration - 1.000
We can see color density (SPEED) on diagram:



And if we set acceleration as 5.000, we can see acceleration:


IT IS WRONG, but we can see reducing density.

How to correctly get formula with acceleration?

Variant like (index = iteration/(4096/228)/speed) and experiments with acceleration (multyplying or divide) don't give correctly result! Who know some info about acceleration?