欧拉函数的递推形式

#include <stdio.h>
int main()
{
int n;
scanf("%d",&n);
int* a=new int[n+1];
for (int i = 1; i < n; i++) a[i] = i;
for (int i = 2; i < n; i += 2) a[i] /= 2;
for (int i = 3; i < n; i += 2)
if(a[i] == i)
{
for (int j = i; j < n; j += i)
a[j] = a[j] / i * (i - 1);
}
for (int i=1;i<n;i++)
printf("%d ",a[i]);
return 0;
}