Kotaro lives alone

An anime about a four year old boy named kotaro who, ironically lives alone. Throughout the series we uncover more of his past neglect from his parents. He lives in an apartment building with a burnt out manga writer and animator, a lady who works as a hostess for those like rent a woman for a night, a man who has a child of divorce and some other lady who no one cares about because she shows up like halfway into the series