The colors he said were "green, black red".
Dunno if you'd call that a=20
preferred value, but I've seen such.
OK, so 5k obviously... Not a common value in any series these days
I think my question would then have been : Are you sure it was a resistor?
I've seen picofuses with those colours (5000mA = 5A), although IIRC, they
normally have a 4th band giving the time-delay charactistics.
-tony