1000以内的质数有
2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,
53,59,61,67,71,73,79,83,89,97,
101,103,107,109,113,127,131,137,139,149,
151,157,163,167,173,179,181,191,193,197,199,
211,223,227,229,233,239,241,
251,257,263,269,271,277,281,283,293,
307,311,313,317,331,337,347,349,
353,359,367,373,379,383,389,397,
401,409,419,421,431,433,439,443,449,
457,461,463,467,479,487,491,499,
503,509,521,523,541,547,
557,563,569,571,577,587,593,599,
601,607,613,617,619,631,641,643,647,
653,659,661,673,677,683,691,
701,709,719,727,733,739,743,
751,757,761,769,773,787,797,
809,811,821,823,827,829,839,
853,857,859,863,877,881,883,887,
907,911,919,929,937,941,947,
953,967,971,977,983,991,997
除了这些就全是合数了