Three's company, they all lived in the same apartment and one of them had to pretend to be gay to stay because of conservative social norms of the time.
Martin elevated one character over the rest and less players.
Splitting hairs but Friends is almost exactly Living Single just with white folks. 6 people living in the same apartment complex but not the same apartment (Living Single was 4 girls/2 guys, Friends even 3/3/ split).
Also, the producer specifically said he thought Living Single was the best thing out and then made a show just like it.