How to plot a summation?

[roadrunner]

That's because the sum function is a cas function and plotting is an operation using home. One way to do it is to make a cas function like:

#cas
sumcas(x):=
BEGIN
return sum(n,n,0,x);
END;
#end

That should work in home and cas; then plot F1(X):=sumcas(X).

-road