Efficient way to compute a tensor

Suppose c is a d-dimensional vector. I want to compute the following third-order tensor

where e_i stands for the ith standard basis of the Euclidean space. Is there a efficient way to compute this? I am using the following for-loop and the Kruskal-tensor ktensor to compute it using the tensor toolbox managed by Sandia National Labs:

x=ktensor({c,c,c});
I=eye(d);

for i=1:d
    x=x+2*c(i)*ktensor({I(:,i),I(:,i),I(:,i)}
end

for i=1:d
    for j=1:d

         x=x- c(i)*c(j)*(ktensor({I(:,i),I(:,i),I(:,j)})+ktensor({I(:,i),I(:,j),I(:,i)})+ktensor({I(:,i),I(:,j),I(:,j)}))


    end
end