数组的左上角:
2, 4, 6, 8, 10, 12, 14, 16, 18, ...
3, 9, 15, 27, 21, 45, 33, 81, 75, ...
5, 25, 35, 125, 55, 175, 65, 625, 245, ...
7, 49, 77, 343, 91, 539, 119, 2401, 847, ...
11, 121, 143, 1331, 187, 1573, 209, 14641, 1859, ...
13, 169, 221, 2197, 247, 2873, 299, 28561, 3757, ...