#include <bits/stdc++.h>
#define rep(i,n) for (int i = 0; i < (n); i ++)
using namespace std;
using ll = long long;
using PL = pair<ll,ll>;
using P = pair<int,int>;
constexpr int INF = 1000000000;
constexpr long long HINF = 1000000000000000;
constexpr long long MOD = 1000000007;
constexpr double EPS = 1e-4;
constexpr double PI = 3.14159265358979;

int main() {
    int N; cin >> N;
    vector<ll> A(N);
    rep(i,N) cin >> A[i];
    rep(i,N) {
        vector<ll> B(N - i - 1);
        rep(j,N - i - 1) {
            B[j] = (A[j] + A[j + 1])%MOD;
        }
        A = B;
    }
    cout << A[0] << endl;
    return 0;
}