Not quite sure, and I'm not quite sure I care either. ;-) However for any multiple of 9, the digits will add up to a multiple of 9. So you're looking for numbe

Not quite sure, and I'm not quite sure I care either. ;-) However for any multiple of 9, the digits will add up to a multiple of 9. So you're looking for numbers in [ (n+2)*9 + 1 for n in range(9) ]