6³=216 which is less than 256, indeed 6 is the largest integer whose cube has this property. Also, 255/5=51₁₀=33₁₆ so we have six values spanning 0..255₁₀, i.e. 0₁₀, 51₁₀, 102₁₀, 153₁₀, 204₁₀, 255₁₀ or 0₁₆, 33₁₆, 66₁₆, 99₁₆, CC₁₆, FF₁₆. These values can be used as the basis of an RGB colour table which will always work "quite well" on machines that use 8-bit graphics and gif-style colour tables.

Quite what you see below depends very much on your computer, your browser, its current image settings and possibly also the operating system. The following TABLE is computed by JavaScript which sets the BGCOLOR attribute of the TABLE cells.

Also take a Java look at the Colour Cube.