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#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

struct path {
	int sum;
	int ways;
};

int main(int argc, char* argv[]) {
	ios_base::sync_with_stdio (false);
	int n, p = 1000000007, i;

	cin >> n ;
	vector<int> d(n + 1);
	for (i = 0; i < n; ++i)
		cin >> d[i];
	d[n] = p;
	sort(d.begin(), d.end());

	vector<path> a[4] = {vector<path>(n*n), vector<path>(n*n), vector<path>(n*n), vector<path>(n*n)};
	int ac[4] = {1, 0, 0, 0};
	int kd = 0, kp = 1, nkd = 2, nkp = 3, xd, xp, e;
	int sum = 0;
	a[0][0].ways = 1;
	path q;

	for (i = 0; i < n + 1; ++i) {
		e = d[i];

		xd = 0;
		xp = 0;
		ac[nkd] = ac[nkp] = 0;
		while(1) {
			if (xd < ac[kd]) {
				if (xp < ac[kp]) {
					if (a[kd][xd].sum > a[kp][xp].sum) {
						q=a[kd][xd];
						xd++;
					} else if (a[kd][xd].sum < a[kp][xp].sum) {
						q=a[kp][xp];
						xp++;
					} else {
						q={a[kp][xp].sum, (a[kp][xp].ways + a[kd][xd].ways) % p};
						xd++;
						xp++;
					}
				} else {
					q=a[kd][xd];
					xd++;
				}
			} else {
				if (xp < ac[kp]) {
					q=a[kp][xp];
					xp++;
				} else {
					break;
				}
			}
			if (e <= q.sum + 1) {
				a[nkd][ac[nkd]++] = {q.sum + e, q.ways};
				a[nkp][ac[nkp]++] = {q.sum, q.ways};
			} else {
				sum = (sum + q.ways) % p;
			}
		}
		e = nkp;
		nkp = kp;
		kp = e;
		e = nkd;
		nkd = kd;
		kd = e;
	}
	sum = (sum + p - 1) % p;
	cout << sum << "\n";
}