I want to plot this expression for some chosen value of 'n':

sum(sum((-1)^{k-j)*binomial(k,j)*j^(n), k=1..n ), j=1..k)

When i do the following:

> E := (-1)^(k-j)*binomial(k,j)*j^(n);

> plot([sum(sum(E,k=1..n),j=1..k)],n=(4..10));

I get: "Warning, unable to evaluate the function to numeric values in the region; see the plotting command's help page to ensure the calling sequence is correct"

I'm a very new user of Maple so i'm probably missing something obvious: please fill me in! :)