def F(a): return dickman_rho(1/a)
def G(a,b): var('z'); return F(a)+RR(integrate(F(a/(1-z))/z,z,a,b))
utab=[2.000, 2.721, 3.200, 3.611, 3.929, 4.237, 4.501, 4.740, 4.969, 5.184, 5.382, 5.569, 5.751, 5.925, 6.091, 6.250, 6.404, 6.553, 6.698, 6.839, 6.975]