is 14 a bad luck number?

so, on the bus ride home tonight i noticed a building that was mostly finished, there were doors at each floor leading to, well, to thin air since the stairs hadn't been built up to them yet. but the weird thing was that there were floor numbers on the doors already and there was no 13th or 14th floor.

now, i know about the no 13th floor (although i do think that it's funny that people are still superstitious enough to not want a 13th floor), but no 14th floor? what's that about?