#include <bits/stdc++.h>

using namespace std;
#define all(x) (x).begin(), (x).end()
template<class T> void check_min(T &a, const T &b){ a = (a < b) ? a : b; }
template<class T> void check_max(T &a, const T &b){ a = (a > b) ? a : b; }
typedef long long ll;

const int N = 300 + 3;
const int MOD = 1e9 + 7;

ll dp[N][2 * N * N], a[N], sum[N], n;

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

    freopen("duel.in", "r", stdin);
    freopen("duel.out", "w", stdout);

    cin >> n;
    for(int i = 1; i <= n; ++i){
        cin >> a[i];
        a[i] *= 2;
    }
    for(int i = 1; i <= n; ++i)
        sum[i] = sum[i - 1] + a[i];

    fill(dp[n + 1], dp[n + 1] + 2 * N * N, 1);
    dp[n + 1][n * (n + 1) / 2] = 0;

    for(int pos = n; pos >= 1; --pos){
        for(int points = 0; points <= n * (n + 1); ++points){
            if(n * (n + 1) - points < points){
                dp[pos][points] = 0;
                continue;
            }
            int other = sum[pos - 1] - points;
            if(n * (n + 1) - other < other){
                dp[pos][points] = 0;
                continue;
            }
            dp[pos][points] = dp[pos + 1][points] + dp[pos + 1][points + a[pos]] + dp[pos + 1][points + a[pos] / 2];
            while(dp[pos][points] >= MOD) dp[pos][points] -= MOD;
            //cout << dp[pos][points] << " - " << pos << " " << points << endl;
        }
    }

    cout << dp[1][0] << "\n";
}