#include <bits/stdc++.h>
using namespace std;
#include <atcoder/modint>
using namespace atcoder;
#ifdef DEFINED_ONLY_IN_LOCAL
#include <dump.hpp>
#define dump(...) cpp_dump(__VA_ARGS__)
#else
#undef dump
#define dump(...)
#endif
#define rep(i, n) for (int i = 0; i < n; i++)
template <class T> istream& operator>>(istream& I, vector<T>& V) { for (T& X : V) I >> X; return I; }

int main() {
    int n;
    cin >> n;
    vector<int> a(n), cnt(500);
    vector<long> s(500);
    cin >> a;
    rep(i, n) a[i]--;
    long ans = 0;
    rep(i, n) {
        rep(j, 500) {
            int x = abs(a[i] - j);
            ans += x * ((long)cnt[j] * i - s[j]) * 2;
        }
        cnt[a[i]]++;
        s[a[i]] += i;
    }
    cout << ans << endl;
    return 0;
}