#include <bits/stdc++.h>
using namespace std;

const int mod = 1e9 + 7;
using Matrix = array<array<int, 80>, 80>;

int add(int a, int b) {
	return (a += b) >= mod ? a - mod : a;
}

int mul(int a, int b) {
	return 1LL * a * b % mod;
}

int modpow(int a, long long b) {
	int ret = 1;
	while (b > 0) {
		if (b & 1) {
			ret = 1LL * ret * a % mod;
		}
		a = 1LL * a * a % mod;
		b >>= 1;
	}
	return ret;
}

Matrix mul(Matrix a, Matrix b) {
	int n = a.size();
	Matrix c = {};
	for (int i = 0; i < n; i++) {
		for (int k = 0; k < n; k++) {
			for (int j = 0; j < n; j++) {
				c[i][j] = add(c[i][j], mul(a[i][k], b[k][j]));
			}
		}
	}
	return c;
}

Matrix pow(Matrix a, long long b) {
	int n = a.size();
	Matrix ret = {};
	for (int i = 0; i < n; i++) {
		ret[i][i] = 1;
	}
	while (b > 0) {
		if (b & 1) {
			ret = mul(ret, a);
		}
		a = mul(a, a);
		b >>= 1;
	}
	return ret;
}

int main() {
	int n;
	long long c;
	cin >> n >> c;

	Matrix mat = {};

	int ans = 0;
	for (int j = 0; j < n; j++) {
		int a;
		cin >> a;
		for (int i = j; i < n; i++) {
			mat[i][j] = a;
		}
		ans = add(ans, mod - modpow(a, c));
	}

	mat = pow(mat, c);

	for (int i = 0; i < n; i++) {
		ans = add(ans, mat[n - 1][i]);
	}

	cout << ans << endl;
}