# include <bits/stdc++.h>
using namespace std;
using i64 = long long;
const int N = 3005; 
int n; i64 a[N], w[N][N], dp[N]; 
int main(void)
{
	scanf("%d", &n);
	for(int i = 1; i <= n; i++) scanf("%lld", &a[i]), a[i] += a[i - 1]; 
	for(int i = 1; i <= n; i++)
	{
		w[i][i] = 0;
	}
	for(int len = 2; len <= n; len++)
	{
		for(int l = 1, r; l + len - 1 <= n; l++)
		{
			r = l + len - 1;
			w[l][r] = w[l + 1][r] + min(2ll * (a[r] - a[l]), 3ll * (r - l) * (a[l] - a[l - 1]) + a[r] - a[l]);
		}
	}
	for(int i = 1; i <= n; i++)
	{
		dp[i] = 1e18;
		for(int j = 0; j < i; j++)
		{
			dp[i] = min(dp[i], dp[j] + w[j + 1][i] + (a[n] - a[i]) * (4ll * (i - j) - 2ll));
		}
	}
	printf("%lld\n", dp[n]);
	return 0;
}