https://s0.wp.com/latex.php?latex=%5Cdisplaystyle%7B%5Csum_%7B%5Calpha%5Ek%3D1%7D%5Csum_%7Bm%3D1%7D%5E%5Cinfty%5Cfrac%7B%5Calpha%28%5Calpha+x%29%5Em%7D%7Bm%7D%3D-%5Csum_%7B%5Calpha%5Ek%3D1%7D%5Calpha%5Clog%281-%5Calpha+x%29%7D.&bg=ffffff&fg=141412&s=0&c=20201002