Let , F(b[1], b[2]), be the (unnormalized) weight of the range of, [[1, 0, 0, 1, 1], [0, 1, 1, 1, 1]], being , [b[1], b[2]] It satisfies the following pure linear recurrece equations with polynomial coefficients g[1] (g[5] + g[4]) F(b[1], b[2]) - -------------------------------- + (-g[1] g[3] - g[1] g[2] + b[1] g[5] (g[3] + g[2]) (2 + b[1]) + b[1] g[4] + g[5] + g[4] - b[2] g[5] - b[2] g[4]) F(b[1] + 1, b[2])/( (g[3] + g[2]) (2 + b[1])) + F(2 + b[1], b[2]) = 0 (g[5] + g[4]) (g[3] + g[2]) F(b[1], b[2]) - ----------------------------------------- - (b[1] g[5] + b[1] g[4] g[1] (b[2] + 2) + g[1] g[3] + g[1] g[2] - b[2] g[5] - b[2] g[4] - g[5] - g[4]) F(b[1], b[2] + 1)/(g[1] (b[2] + 2)) + F(b[1], b[2] + 2) = 0 These recurrences enable to compute, in linear time any desired value of , F(b[1], b[2]) subject to the inital conditions [[g[5] + g[4] + (g[3] + g[2]) g[1], 2 (g[5] + g[4]) (g[3] + g[2]) + 1/2 (g[3] + g[2]) g[1]], [ 2 2 g[1] (g[5] + g[4]) + 1/2 (g[3] + g[2]) g[1] , 1/2 (g[5] + g[4]) 2 2 + (g[3] + g[2]) g[1] (g[5] + g[4]) + 1/4 (g[3] + g[2]) g[1] ]]