1.理论部分
1.1.素数
A natural number (1, 2, 3, 4, 5, 6, etc.) is called a prime number (or a prime) if it is greater than 1 and cannot be written as a product of two natural numbers that are both smaller than it. (from Wikipedia)
如果一个自然数(如1, 2, 3, 4, 5, 6)大于1并且不能看作小于他的两个自然数的乘积,那么这个自然数称为一个素数(或质数)。
如:5=1×5 素数
6=2×3 非素数