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.