import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		long[] a = new long[n];
		for (int i = 0; i < n; i++) {
			a[i] = sc.nextLong();
		}
		sc.close();

		for (int i = n - 1; i > 0; i--) {
			long[] b = new long[n];
			for (int j = 0; j < i; j++) {
				b[j] = a[j] + a[j + 1];
				b[j] %= 1000000007;
			}
			a = b;
		}
		System.out.println(a[0] % 1000000007);
	}
}