using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Numerics;
using System.Threading.Tasks;
using static System.Console;
using static System.Math;
using static Func;
class Z { static void Main() => new K(); }
class K
{
	int F => int.Parse(Str);
	long FL => long.Parse(Str);
	int[] G => Strs.Select(int.Parse).ToArray();
	uint[] GU => Strs.Select(uint.Parse).ToArray();
	decimal[] GD => Strs.Select(decimal.Parse).ToArray();
	long[] GL => Strs.Select(long.Parse).ToArray();
	string Str => ReadLine();
	string[] Strs => Str.Split(new char[] { ' ', '\t' }, StringSplitOptions.RemoveEmptyEntries);
	static ulong One(int k) => 1ul << k;
	static ulong All(int k) => One(k) - 1;
	static bool Has(ulong s, int k) => (s & One(k)) != 0;
	const int MOD = 1000000007;
	public K()
	{
		SetOut(new StreamWriter(OpenStandardOutput()) { AutoFlush = false });
		Solve();
		Out.Flush();
	}
	void Solve()
	{
		N = F;
		A = G;
		WriteLine(Calc(0, N - 1, 1, 1) + A[0] + A[N - 1]);
	}
	int N;
	int[] A;
	Dictionary<Pair, long> memo = new Dictionary<Pair, long>();
	long Calc(int l, int r, long wl, long wr) => Calc(new Pair(l, r, wl, wr));
	long Calc(Pair p)
	{
		if (p.r - p.l <= 1) return 0;
		if (!memo.ContainsKey(p))
		{
			var w = p.wl + p.wr;
			memo[p] = long.MaxValue;
			for (var i = p.l + 1; i < p.r; i++) memo[p] = Min(memo[p], w * A[i] + Calc(p.l, i, p.wl, w) + Calc(i, p.r, w, p.wr));
		}
		return memo[p];
	}
}
struct Pair : IEquatable<Pair>
{
	public readonly int l, r;
	public readonly long wl, wr;
	public Pair(int l, int r, long wl, long wr) { this.l = l; this.r = r; this.wl = wl; this.wr = wr; }
	public bool Equals(Pair other) => l == other.l && r == other.r && wl == other.wl && wr == other.wr;
	public override int GetHashCode() => CombineHashCodes(l.GetHashCode(), r.GetHashCode(), wl.GetHashCode(), wr.GetHashCode());
	static int CombineHashCodes(int h1, int h2) => (((h1 << 5) + h1) ^ h2);
	static int CombineHashCodes(int h1, int h2, int h3, int h4) => CombineHashCodes(CombineHashCodes(h1, h2), CombineHashCodes(h3, h4));
}
static class Func
{
	public static T[] ConstantArray<T>(int n, T val) { var a = new T[n]; for (var i = 0; i < n; i++) a[i] = val; return a; }
	public static T[] MakeArray<T>(int n, Func<int, T> f) { var a = new T[n]; for (var i = 0; i < n; i++) a[i] = f(i); return a; }
	public static T[] Recurse<T>(int n, T a0, Func<int, T, T> f) { var a = new T[n]; a[0] = a0; for (var i = 1; i < n; i++) a[i] = f(i, a[i - 1]); return a; }
	public static T[] Accumulate<T>(IList<T> a, T zero, Func<T, T, T> f) { var s = new T[a.Count + 1]; s[0] = zero; for (var i = 0; i < a.Count; i++) s[i + 1] = f(s[i], a[i]); return s; }
	public static int FirstBinary(int min, int max, Predicate<int> pred)
	{
		while (min < max)
		{
			var mid = (min + max) / 2;
			if (pred(mid)) max = mid;
			else min = mid + 1;
		}
		return min;
	}
	public static long GCD(long a, long b)
	{
		var n = (ulong)Abs(a); var m = (ulong)Abs(b);
		if (n == 0) return (long)m; if (m == 0) return (long)n;
		int zm = 0, zn = 0;
		while ((n & 1) == 0) { n >>= 1; zn++; }
		while ((m & 1) == 0) { m >>= 1; zm++; }
		while (m != n)
		{
			if (m > n) { m -= n; while ((m & 1) == 0) m >>= 1; }
			else { n -= m; while ((n & 1) == 0) n >>= 1; }
		}
		return (long)n << Min(zm, zn);
	}
	public static long Mod(long a, long mod) => (a % mod + mod) % mod;
	public static long Inverse(long a, long mod) => Mod(SolveLinear(Mod(a, mod), mod)[0], mod);
	public static long Pow(long a, long b, long mod)
	{
		var p = 1L;
		var x = a;
		while (b > 0)
		{
			if ((b & 1) == 1) p = (p * x) % mod;
			b >>= 1;
			x = (x * x) % mod;
		}
		return p;
	}
	public static long[] SolveLinear(long n, long m)
	{
		var A = new long[,] { { n < 0 ? -1 : 1, 0 }, { 0, m < 0 ? -1 : 1 } };
		n = Abs(n); m = Abs(m);
		while (m > 0)
		{
			long q = n / m, r = n % m;
			n = m; m = r;
			for (var i = 0; i < 2; i++)
			{
				var x = A[i, 1];
				A[i, 1] = A[i, 0] - q * x;
				A[i, 0] = x;
			}
		}
		return new long[] { A[0, 0], A[1, 0] };
	}
}


Measured memory_bytes: 39520