【数论】 HDOJ 5407 CRB and Candies

数论结论题。。。就是1-n+1的lcm除以n+1。。。。不知道结论怎么做？----没法做。。。

#include <bits/stdc++.h>
using namespace std;
typedef long long LL;

const int maxn = 1000005;
const int N = 1000000;
const int mod = 1e9+7;

int val[maxn];
LL f[maxn];
LL g[maxn];
int p[maxn];

LL powmod(LL a, LL b)
{
	LL res = 1, base = a;
	while(b) {
		if(b % 2) res = res * base % mod;
		base = base * base % mod;
		b /= 2;
	}
	return res;
}

void init()
{
	for(int i = 2; i < maxn; i++) if(p[i] == 0)
		for(int j = i + i; j < maxn; j += i) p[j] = 1;
	
	for(int i = 2; i < maxn; i++) if(p[i] == 0)
		for(LL j = (LL)i; j < maxn; j *= i)
			val[j] = i;
	f[1] = 1;
	for(int i = 2; i < maxn; i++) 
		if(val[i]) f[i] = f[i-1] * val[i] % mod;
		else f[i] = f[i-1];
	for(int i = 1; i <= N; i++) g[i] = f[i+1] * powmod(i+1, mod-2) % mod;
}

int main()
{
	init();
	int _;
	scanf("%d", &_);
	while(_--) {
		int x;
		scanf("%d", &x);
		printf("%lld\n", g[x]);
	}
	
	return 0;
}