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

#include<atcoder/all>
using namespace atcoder;
using mint=atcoder::modint998244353;

#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")

#define int long long


signed main(){
	int N;cin>>N;
	vector<int> A(N);for(auto&&e:A)cin>>e,e--;
	vector<int> sum(509);
	vector<int> cnt(509);

	int ans=0;

	for(int i=0;i<N;i++){
		for(int j=0;j<500;j++){
			ans+=abs(j-A[i])*(i*cnt[j]-sum[j]);
		}

		sum[A[i]]+=i;
		cnt[A[i]]+=1;
	}

	cout<<2*ans<<endl;
}