HDU5673 Robot 默慈金数

#include<iostream>
#include<algorithm>
#include<set>
#include<vector>
#include<queue>
#include<cstdlib>
#include<cstdio>
#include<cstring>
#include<cmath>
using namespace std;
typedef long long LL;
typedef unsigned long long ULL;
const int N=1e6+5;
const LL mod=1e9+7;
LL f
,inv
;
int main(){
inv[1]=1;
for(int i=2;i<N;++i)
inv[i]=inv[mod%i]*(mod-mod/i)%mod;
f[0]=1;
f[1]=1;
for(int i=2;i<=N-5;++i)
f[i]=((2*i+1)*f[i-1]%mod+(3*i-3)*f[i-2]%mod)%mod*inv[i+2]%mod;
int T,n;
scanf("%d",&T);
while(T--){
scanf("%d",&n);
printf("%I64d\n",f
);
}
return 0;
}