sorted by hamming weight

pseudocode:

c=0
for i = 0..(256^3)-1:
  w = hamming_weight(i)
  c = count[w]
  weight[w][c]=i
  count[w] = c + 1

for c=0..24:
  w = 0
  do {
    out = weight[c][w]
    if ( out != 0 ^^ c == 0 )
      pixelRGB = out
  } while ( out != 0)