Hi Jay,
I assume that the following is the equation you are trying to implement and plot,
The following code demonstrates this,
n = -4:2;
x = [2,4,-3,1,-5,4,7];
% padding zeros
X = [0,0,0,0,0,x];
y = zeros(1,length(n));
for i = 1:length(y)
y(i) = i*(X(i) + X(i+1) + X(i+2) + X(i+3) + X(i+4));
end
stem(n,y)