3 ms·It's just the fact that 1, 10, 100, 1000, ... = 1, 3, 2, -1, -3, -2, ... (repeating) mod 7by meiji163 5y agoIt's just the fact that 1, 10, 100, 1000, ... = 1, 3, 2, -1, -3, -2, ... (repeating) mod 7