Write a function called bell that returns the first n rows of the Bell triangle, where n is an input argument.The function must return an n-by-n array where the top left triangle contains the Bell triangle with each row of the Bell triangle positione

n = 7;
a = zeros(n);
a(1) = 1;
for k = 1:n-1
   a(k+1,1:k+1) = cumsum(a(k,[k,1:k]),2);
end

[Walter Roberson]

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