这个程序较前者1，有些更改，是将一些素数先求出来存入数组备用。所以当所求范围较大如间隔为200万，500万，时若使用该程序可比qiusushu1节约1---2分钟-This procedure than the former one, and some change is to first seek out a number of prime numbers into an array of backup. So when not asked for a wider range such as the interval of 2 million, 500 million, The use of the program is comparable qiusushu1 saving 1--- 2 minutes! ! !