A high quality contribution but an annoying error is present in my published article
It is probably best to do all of that. Contact the editor and ask if a correction can be published (letters to editor, ...). Put out a corrected version somewhere visible. 

But also, don't obsess over it. Perfection is rarely attainable in an imperfect world with imperfect humans. 

The sort of error you mention is very common, actually. Once you write something it is difficult for you to read it as incorrect. Often your mind "reads" what you think is supposed to be on the page rather than what is actually there. It is notoriously difficult for people to proofread their own work. 

Ideally, the review process should have caught the inconsistency, but since it wasn't caught, others glossed over it also as immaterial to what your arguments are.