#define _GLIBCXX_DEBUG
#define ll long long
#include <bits/stdc++.h>
using namespace std;
using Graph = vector<vector<int>>;

int main(){
  int N; cin >> N;
  vector<ll> A(N);
  for(int i = 0; i < N; i++) cin >> A[i];
  for(int i = N-1; i > 0; i--){
    vector<ll> B(i);
    for(int j = 0; j < i; j++){
      B[j] = A[j] + A[j+1];
      B[j] %= 1000000007;
    }
    for(int j = 0; j < i; j++){
      A[j] = B[j];
    }
    if(i == 1) cout << A[0] << endl;
  }
}