The 216 non-dithering colors

(Non-dithering color codes by Lynda Weinman.)

Will look like the color you ask for on all browsers and all computer screen resolution settings because these are the 216 colors chosen by Windows and MAC operating platforms to make up their palettes of colors. The colors that aren't represented here are the colors that these try to create by dithering.

They arise by using 00, 33, 66, 99, CC, and FF in the hex codes.