This question of counting the number of lattice points a distance sqrt(N) away from the origin involves adding up the value of this simple function over all divisors of N. Now, remember why we're doing all of this.
这个原点 sqrt(N) 离的格点数量的问题涉及将这个简单函数的值与 N 的所有除数相加。 现在,请记住我们为什么要做这一切。
Numbers with lots of factors have lots of divisors, primes only have two divisors, and you might think that you'd need perfect knowledge of the distribution of primes to get anything useful out of this.