#include <bits/stdc++.h>

using namespace std;

using ll = long long;

ll select_kth(vector<ll>& a, int start, int end, int k) {
    int sz = end - start;
    vector<ll> v(sz);
    for (int i = 0; i < sz; i++) v[i] = a[i + start];
    nth_element(v.begin(), v.begin() + k, v.end());
    return v[k];
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int n;
    cin >> n;
    vector<ll> a(n);
    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }

    ll ans = 0;
    for (int k = 1; k <= n; k++) {
        int max_num = n / k;
        vector<ll> memoL(max_num + 1, 0);
        ll tmp = 0;
        for (int i = 0; i < max_num; i++) {
            tmp += select_kth(a, i * k, (i + 1) * k, (k - 1) / 2) * k;
            memoL[i + 1] = max(memoL[i], tmp);
        }

        vector<ll> memoR(max_num + 1, 0);

        tmp = 0;
        for (int i = 0; i < max_num; i++) {
            tmp += select_kth(a, n - (i + 1) * k, n - i * k, (k - 1) / 2) * k;
            memoR[i + 1] = max(memoR[i], tmp);
        }

        for (int i = 0; i <= max_num; i++) {
            ans = max(ans, memoL[i] + memoR[max_num - i]);
        }
    }
    cout << ans << "\n";
    return 0;
}