Clarification on this function

I'm trying to draw the graph of the function $\displaystyle f(x)=(x-4)^{\frac{2}{3}}$ and I'm a little confused. Firstly, is the y-intercept:

$\displaystyle =(-4)^{\frac{2}{3}}$

$\displaystyle =16^{\frac{1}{3}}$?

Because when I entered this function into an online graphing calculator, it showed the graph only existing on $\displaystyle x>4$. I also tried inputting it on WolframAlpha and got to a completely different graph: http://www.wolframalpha.com/input/?i=(x-4)^(2/3)