Comment by keepamovin

Haha you are right! I might have been thinking of that, thanks for your charitable generous interpretation - or I might have been confused. I think I was just confused here, but good point.

I guess it's the n/2 one whose divisibility by 2 becomes uncertain. I think I looked at the formula and thought 3n+ 1 if 3n + 1 ~ 1 (mod 2), not 'if n ~ 1' haha that was funny! :)

Thanks again :)

edit: Also what a lovely way to correct someone -- 'said what you mean' -- I am gonna use that! :)