C++ :

#include <cstdio>
#include <cstring>
#include <algorithm>
#define ll long long
using namespace std;
ll n, a[3010], s[3010], d;
ll g[3010][3010], f[3010];

inline int read() {
    int x = 0;
    char c = getchar();
    while (c < '0' || c > '9') c = getchar();
    while (c >= '0' && c <= '9') x = (x << 1) + (x << 3) + (c ^ 48), c = getchar();
    return x;
}

int main() {
    n = read();
    for (int i = 1; i <= n; i++) a[i] = read(), s[i] = s[i - 1] + a[i];
    for (int j = 1; j < n; j++)
        for (int i = 1; i <= n - j; i++)
            g[i][i + j] = g[i + 1][i + j] + min((s[i + j] - s[i]) * 2, 3 * j * a[i] + s[i + j] - s[i]);
    memset(f, 5, sizeof(f));
    f[0] = 0;
    for (int i = 1; i <= n; i++)
        for (int j = 0; j < i; j++)
            f[i] = min(f[i], f[j] + g[j + 1][i] + (3 * (i - j - 1) + i - j + 1) * (s[n] - s[i]));
    printf("%lld\n", f[n]);
    return 0;
}