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

#define For(i, a, b) for(int i = (a); i < (b); i++)
#define rep(i, n) For(i, 0, n)
#define rFor(i, a, b) for(int i = (a); i >= (b); i--)
#define ALL(v) (v).begin(), (v).end()
#define rALL(v) (v).rbegin(), (v).rend()

using lint = long long;
using ld = long double;

int INF = 2000000000;
lint LINF = 1000000000000000000;

struct SetupIo {
    SetupIo() {
        ios::sync_with_stdio(false);
        cin.tie(nullptr);
        cout << fixed << setprecision(15);
    }
} setupio;

template <class T>
struct PrefixSum {
    int n;
    vector<T> s;
    
    PrefixSum() {}
    PrefixSum(vector<T> &a) : n(a.size()), s(n + 1, T(0)) {
        for (int i = 0; i < n; i++) {
            s[i + 1] = s[i] + a[i];
        }
    }
   
    // [l, r)
    T prod(int l, int r) {
        assert(0 <= l && l <= r && r <= n);
        return (l == r ? T(0) : s[r] - s[l]);
    }
};

int main() {
    int n;
    cin >> n;
    vector<vector<lint>> id(510);
    rep(i, n) {
        int x;
        cin >> x;
        id[x].emplace_back(i);
    }
    vector<PrefixSum<lint>> sum(510);
    rep(i, 510) {
        sum[i] = PrefixSum<lint>(id[i]);
    }
    lint ans = 0;
    rep(i, 510) {
        if (id[i].size() == 0) { continue; }
        For(j, i + 1, 510) {
            if (id[j].size() == 0) { continue; }
            lint d = j - i;
            rep(k, int(id[i].size())) {
                int b = upper_bound(ALL(id[j]), id[i][k]) - id[j].begin();
                int sz = id[j].size();
                ans += (lint(id[i][k]) * lint(b) - sum[j].prod(0, b)) * d;
                ans += (sum[j].prod(b, sz) - lint(id[i][k]) * lint(sz - b)) * d;
            }
        }
    }
    ans *= 2LL;
    cout << ans << "\n";
}