I absolutely agree, I even like the question. The difference to the coding interview is that nobodys time is wasted. It is a very quick question and if you get

I absolutely agree, I even like the question. The difference to the coding interview is that nobodys time is wasted. It is a very quick question and if you get a slightly confused "16" back, you can just move on to more relevant matters. This is different to a 30 minute long question where you examine the applicants ability to solve first year undergrad homework. But that you are asking the question at all speaks by itself for major problems in employment.