In truth there are not all that many vivid colours anyway.
1536 of them in the HSV model with 256 values for RGB.
Or 36,001 if Hue is 0-359 degrees and Value is 0 to 100% (Saturation is 100%).http://www.csgnetwork.com/csgcolorsel4.html
250R/200G/200B = 0°H/20%S/98%V
Inserting 255 in one position:
255R/200G/200B = 0°H/22%S/100%V
250R/255G/200B = 65°H/22%S/100%V
250R/200G/255B = 295°H/22%S/100%V
In all three cases the saturation value is only 22%, very pastel.
Inserting 0 in one position:
0R/200G/200B = 180°H/100%S/78%V
250R/0G/200B = 312°H/100%S/98%V
250R/200G/0B = 48°H/100%S/98%V
In all three cases the saturation value is 100%, quite vivid.