Very interesting, seems your remembering looks correct to me.

x / (x+y+1) :: https://www.wolframalpha.com/input/?i=plot+x+%2F%28x+%2B+y+%...

horrendous formula :: https://www.wolframalpha.com/input/?i=plot+%28%28x%2F%28x%2B...

Much less prone to typos.