先看一个矩阵:1934年,一个来自东印度(现在的孟加拉国)的普通学者——钱德拉,在数论领域中取得了一个辉煌成就,这个成就使他青史留名,永垂不朽。钱德拉的正方形筛子的第一横行是首项为4,相邻两数之差为3的等差数列:4,7,10,…(可以一直写下去,永远写不到头)。第二行,第三行,……以后的任何一行也都是等差数列,只不过相邻两数之差逐渐变大,分别是5,7,9,11,13,…而且都是奇数。 Consider a Matrix: In 1934, Chandra, an ordinary scholar from East India (now Bangladesh), made a brilliant achievement in the field of number theory, a accomplishment that made his history famous and immortal. The first row of Chandra’s square sieve is the first of four, the difference between two consecutive numbers of 3 arithmetic sequence: 4,7,10, ... (you can write down forever, never write the head). The second line, the third line, ...... any subsequent line is also the arithmetic sequence, but the difference between the two adjacent numbers gradually become larger, respectively 5,7,9,11,13, ... and are all odd .