双倍经验题过了，本题没过。

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

#define inv(x) quick_pow(x,MOD-2)
const int MAXN=1e6+5;
const int MOD=998244353;
int a[MAXN],cnt[MAXN],f[MAXN],g[MAXN];
int u[MAXN],p[MAXN],tot;
bool not_prime[MAXN];
void init()
{
    u[1]=1;
    for(int i=2;i<MAXN;++i)
    {
        if(!not_prime[i]) p[++tot]=i,u[i]=-1;
        for(int j=1;j<=tot && i*p[j]<MAXN;++j)
        {
            not_prime[i*p[j]]=1;
            if(i%p[j]==0) break;
            u[i*p[j]]=-u[i];
        }
    }
}
int quick_pow(int a,int b)
{
    int ret=1;
    while(b)
    {
        if(b&1) ret=(long long)ret*a%MOD;
        a=(long long)a*a%MOD,b>>=1;
    }
    return ret;
}
int main()
{
    init();
    int n;
    cin>>n;
    int maxn=0,sum=0;
    for(int i=1;i<=n;++i) scanf("%d",&a[i]),++cnt[a[i]],maxn=max(maxn,a[i]),(sum+=a[i])%=MOD;
    for(int i=1;i<=maxn;++i)
    {
        for(int j=i;j<=maxn;j+=i) (g[i]+=(long long)cnt[j]*j%MOD)%=MOD;
        g[i]=(long long)g[i]*g[i]%MOD;
    }
    for(int i=1;i<=maxn;++i) for(int j=i;j<=maxn;j+=i) (f[i]+=((long long)u[j/i]*g[j]%MOD+MOD)%MOD)%=MOD;
    int ans=0;
    for(int i=1;i<=maxn;++i) (ans+=(long long)f[i]*inv(i)%MOD)%=MOD;
    //ans=(long long)(ans-sum+MOD)*inv(2)%MOD;
    cout<<ans;
    return 0;
}