RT，我自己也想不明白，本地拍小数据也都过了。

提交记录TLE40pts

#include <cstdio>
#include <algorithm>
#include <iostream>
#include <cstring>
#include <cmath>
#include <vector>
#include <map>
#include <cstdlib>
#include <deque>
#define int long long
using namespace std;
int rd() {
	int sum=0,f=1; char ch=getchar();
	while(!isdigit(ch)) {
		if(ch=='-') f=-1; ch=getchar(); 
	}
	while(isdigit(ch)) sum=sum*10+ch-'0',ch=getchar();
	return sum*f;
}
#define N (int)(3e5+5)
int n,a[N],f[N];

bool cmp(int x,int y) {
	return x>y;
}
int ans=0;
int gcd(int x,int y) {
	return !y?x:gcd(y,x%y);
}
int lcm(int x,int y) {
	return x/gcd(x,y)*y;
}
signed main() {
	n=rd(); for(int i=1;i<=n;i++) a[i]=rd(); 
	sort(a+1,a+1+n,cmp);
	for(int i=1;i<=n;i++) {
		f[i]=a[i];
		for(int j=i-1;j>=1;j--) {
			if(a[i]==a[j]) f[i]=max(f[i],f[j]+(i-j)*a[i]);
			else if(a[j]+a[i]+gcd(a[j],a[i])==lcm(a[j],a[i])) f[i]=max(f[i],f[j]+a[i]);
		}
		ans=max(ans,f[i]);
	}
	cout<<ans;
	return 0;
}