#include<iostream>
#include<vector>
#include<string>
#include<cstring>
#include<algorithm>
#include<map>
#include<set>
#include<cmath>
#include<cassert>
#include<queue>

using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef vector<int> vi;

typedef long long number;
typedef vector<number> vec;
typedef vector<vec> matrix;

ll mod_pow(ll x, ll p, ll MOD) {
    ll a = 1;
    while (p) {
        if (p%2) a = a*x%MOD;
        x = x*x%MOD;
        p/=2;
    }
    return a;
}

const ll MOD = 1e9+7;

// O( n )
matrix iden(int n) {
    matrix A(n, vec(n));
    for (int i = 0; i < n; ++i) A[i][i] = 1;
    return A;
}
// O( n^3 )
matrix mul(const matrix &A, const matrix &B) {
    matrix C(A.size(), vec(B[0].size()));
    for (int i = 0; i < (int)C.size(); ++i)
        for (int j = 0; j < (int)C[i].size(); ++j)
            for (int k = 0; k < (int)A[i].size(); ++k) {
                C[i][j] += A[i][k] * B[k][j];
                C[i][j] %= MOD;
            }
    return C;
}
// O( n^3 log e )
matrix pow(const matrix &A, ll e) {
    if (e == 0) return iden(A.size());
    if (e == 1) return A;
    if (e % 2 == 0) {
        matrix tmp = pow(A, e/2);
        return mul(tmp, tmp);
    } else {
        matrix tmp = pow(A, e-1);
        return mul(A, tmp);
    }
}

int A[111];

int main() {
	int N;
	ll C;
	cin >> N >> C;
	if (C == 1) {
		cout << 0 << endl;
		return 0;
	}
	for (int i = 0; i < N; i++)
		cin >> A[i];
	matrix M(N, vec(N));
	for (int i = 0; i < N; i++) {
		for (int j = 0; j <= i; j++) {
			M[i][j] = A[i];
		}
	}
	M = pow(M, C);
	ll ans = 0;
	for (int i = 0; i < N; i++)
		ans += M[i][0];
	for (int i = 0; i < N; i++) {
		ans -= mod_pow(A[i], C, MOD);
	}
	ans = ((ans%MOD)+MOD)%MOD;
	cout << ans << endl;
	return 0;
}