#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#include <stack>
#include <unordered_set>
#include <unordered_map>

using namespace std;

ifstream inF("duel.in");
ofstream outF("duel.out");

#define cin inF
#define cout outF

const int MAX_N = 305;

typedef unsigned long long ull;
typedef long long sll;

const sll MOD = 1e9 + 7;

sll n;
sll p[MAX_N];

sll ans;

void input()
{
    cin >> n;
    for (int i = 0; i < n; ++i)
    {
        cin >> p[i];
        p[i] *= 2;
    }
}

void output()
{
    cout << ans << "\n";
}

const sll MAX_SCORE = 3 * MAX_N * MAX_N;

sll dp[MAX_N + 1][MAX_SCORE];
sll totalScore[MAX_N + 1];

void solve()
{
    totalScore[0] = 0;
    for (int i = 0; i < n; ++i)
    {
        totalScore[i + 1] = totalScore[i] + p[i];
    }

    dp[0][0] = 1;

    for (int i = 1; i < n; ++i)
    {
        double maxScore = totalScore[n] / 2;
        double minScore = std::max(0.0, totalScore[i] - maxScore);
        double prevMinScore = std::max(0.0, totalScore[i - 1] - maxScore);
        //std::cerr << i << " -- " << maxScore << " " << minScore << " " << prevMinScore << ": " << std::endl;
        for (int j = minScore + 0.75; j <= maxScore; ++j)
        {
            dp[i][j] = 0;
            if (j - p[i - 1] >= prevMinScore) dp[i][j] += dp[i - 1][j - p[i - 1]];
            if (j - p[i - 1] / 2 >= prevMinScore) dp[i][j] += dp[i - 1][j - p[i - 1] / 2];
            if (j >= prevMinScore) dp[i][j] += dp[i - 1][j];
            dp[i][j] %= MOD;
        }
    }

    double maxScore = totalScore[n] / 2;
    double minScore = std::max(0.0, totalScore[n - 1] - maxScore);

    ans = 0;
    for (int j = minScore + 0.75; j <= maxScore; ++j)
    {
        if (j + p[n - 1] != maxScore) ans += dp[n - 1][j];
        if (j + p[n - 1] / 2 != maxScore) ans += dp[n - 1][j];
        if (j != maxScore) ans += dp[n - 1][j];
        ans %= MOD;
    }
}

int main()
{
    std::ios::sync_with_stdio(false);
    cin.tie(nullptr);

    /*int t;
    cin >> t;
    for (int i = 0; i < t; ++i)*/
    {
        input();
        solve();
        output();
    }

    return 0;
}