function A3x = A3coeff(n) %A3COEFF Evaluate coefficients for A_3 % % A3x = A3COEFF(n) evaluates the coefficients of epsilon^l in Eq. (24). % n is a scalar. A3x is a 1 x 6 array. persistent coeff nA3 if isempty(coeff) nA3 = 6; coeff = [ ... -3, 128, ... -2, -3, 64, ... -1, -3, -1, 16, ... 3, -1, -2, 8, ... 1, -1, 2, ... 1, 1, ... ]; end A3x = zeros(1, nA3); o = 1; k = 1; for j = nA3 - 1 : -1 : 0 m = min(nA3 - j - 1, j); A3x(k) = polyval(coeff(o : o + m), n) / coeff(o + m + 1); k = k + 1; o = o + m + 2; end end