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

#define rep(i,n) for(long long i = 0; i < (long long)(n); i++)
#define repi(i,a,b) for(long long i = (long long)(a); i < (long long)(b); i++)
using ll = long long; using vll = vector<ll>; using vvll = vector<vll>; 
static const long long mo = 1e9+7;

template <typename T, typename U> ostream &operator<<(ostream &o, const pair<T, U> &v) {  o << "(" << v.first << ", " << v.second << ")"; return o; }
template<size_t...> struct seq{}; template<size_t N, size_t... Is> struct gen_seq : gen_seq<N-1, N-1, Is...>{}; template<size_t... Is> struct gen_seq<0, Is...> : seq<Is...>{};
template<class Ch, class Tr, class Tuple, size_t... Is>
void print_tuple(basic_ostream<Ch,Tr>& os, Tuple const& t, seq<Is...>){ using s = int[]; (void)s{0, (void(os << (Is == 0? "" : ", ") << get<Is>(t)), 0)...}; }
template<class Ch, class Tr, class... Args> 
auto operator<<(basic_ostream<Ch, Tr>& os, tuple<Args...> const& t) -> basic_ostream<Ch, Tr>& { os << "("; print_tuple(os, t, gen_seq<sizeof...(Args)>()); return os << ")"; }
ostream &operator<<(ostream &o, const vvll &v) { rep(i, v.size()) { rep(j, v[i].size()) o << v[i][j] << " "; cout << endl; } return o; }
template <typename T> ostream &operator<<(ostream &o, const vector<T> &v) { o << '['; rep(i, v.size()) o << v[i] << (i != v.size()-1 ? ", " : ""); o << "]";  return o; }
template <typename T>  ostream &operator<<(ostream &o, const set<T> &m) { o << '['; for (auto it = m.begin(); it != m.end(); it++) o << *it << (next(it) != m.end() ? ", " : ""); o << "]";  return o; }
template <typename T, typename U>  ostream &operator<<(ostream &o, const map<T, U> &m) { o << '['; for (auto it = m.begin(); it != m.end(); it++) o << *it << (next(it) != m.end() ? ", " : ""); o << "]";  return o; }
template <typename T, typename U>  ostream &operator<<(ostream &o, const unordered_map<T, U> &m) { o << '['; for (auto it = m.begin(); it != m.end(); it++) o << *it; o << "]";  return o; }
void printbits(ll mask, ll n) { rep(i, n) { cout << !!(mask & (1ll << i)); } cout << endl; }
#define ldout fixed << setprecision(40) 

class Mod {
    public:
        int num;
        int mod;
        Mod() : Mod(0) {}
        Mod(long long int n) : Mod(n, 1000000007) {}
        Mod(long long int n, int m) { mod = m; num = (n % mod + mod) % mod;}
        Mod(const string &s){ long long int tmp = 0; for(auto &c:s) tmp = (c-'0'+tmp*10) % mod; num = tmp; }
        Mod(int n) : Mod(static_cast<long long int>(n)) {}
        operator int() { return num; }
        void setmod(const int mod) { this->mod = mod; }
};
istream &operator>>(istream &is, Mod &x) { long long int n; is >> n; x = n; return is; }
ostream &operator<<(ostream &o, const Mod &x) { o << x.num; return o; }
Mod operator+(const Mod a, const Mod b) { return Mod((a.num + b.num) % a.mod); }
Mod operator+(const long long int a, const Mod b) { return Mod(a) + b; }
Mod operator+(const Mod a, const long long int b) { return b + a; }
Mod operator++(Mod &a) { return a + Mod(1); }
Mod operator-(const Mod a, const Mod b) { return Mod((a.mod + a.num - b.num) % a.mod); }
Mod operator-(const long long int a, const Mod b) { return Mod(a) - b; }
Mod operator--(Mod &a) { return a - Mod(1); }
Mod operator*(const Mod a, const Mod b) { return Mod(((long long)a.num * b.num) % a.mod); }
Mod operator*(const long long int a, const Mod b) { return Mod(a)*b; }
Mod operator*(const Mod a, const long long int b) { return Mod(b)*a; }
Mod operator*(const Mod a, const int b) { return Mod(b)*a; }
Mod operator+=(Mod &a, const Mod b) { return a = a + b; }
Mod operator+=(long long int &a, const Mod b) { return a = a + b; }
Mod operator-=(Mod &a, const Mod b) { return a = a - b; }
Mod operator-=(long long int &a, const Mod b) { return a = a - b; }
Mod operator*=(Mod &a, const Mod b) { return a = a * b; }
Mod operator*=(long long int &a, const Mod b) { return a = a * b; }
Mod operator*=(Mod& a, const long long int &b) { return a = a * b; }
Mod factorial(const long long n) {
    if (n < 0) return 0;
    Mod ret = 1;
    for (int i = 1; i <= n; i++) {
        ret *= i;
    }
    return ret;
}
Mod operator^(const Mod a, const long long n) {
    if (n == 0) return Mod(1);
    Mod res = (a * a) ^ (n / 2);
    if (n % 2) res = res * a;
    return res;
}
Mod modpowsum(const Mod a, const long long b) {
    if (b == 0) return 0;
    if (b % 2 == 1) return modpowsum(a, b - 1) * a + Mod(1);
    Mod result = modpowsum(a, b / 2);
    return result * (a ^ (b / 2)) + result;
}


/*************************************/
// 以下、modは素数でなくてはならない！
/*************************************/
Mod inv(const Mod a) { return a ^ (a.mod - 2); }
Mod operator/(const Mod a, const Mod b) { assert(b.num != 0); return a * inv(b); }
Mod operator/(const long long int a, const Mod b) { assert(b.num != 0); return Mod(a) * inv(b); }
Mod operator/=(Mod &a, const Mod b) { assert(b.num != 0); return a = a * inv(b); }

// n!と1/n!のテーブルを作る。
// nCrを高速に計算するためのもの。
//
// assertでnを超えていないかをきちんとテストすること。
//
// O(n log mo)
vector<Mod> fact, rfact;
void constructFactorial(const long long n) {
    fact.resize(n);
    rfact.resize(n);
    fact[0] = rfact[0] = 1;
    for (int i = 1; i < n; i++) {
        fact[i] = fact[i-1] * i;
        rfact[i] = Mod(1) / fact[i];
    }
}

// O(1)
Mod nCr(const long long n, const long long r) {
//    assert(n < (long long)fact.size());
    if (n < 0 || r < 0) return 0;
    return fact[n] * rfact[r] * rfact[n-r];
}

// O(k log mo) 
Mod nCrWithoutConstruction(const long long n, const long long k) {
    if (n < 0) return 0;
    if (k < 0) return 0;
    Mod ret = 1;
    for (int i = 0; i < k; i++) {
        ret *= n - (Mod)i;
        ret /= Mod(i+1);
    }
    return ret;
}
// n*mの盤面を左下から右上に行く場合の数
// O(1)
Mod nBm(const long long n, const long long m) {
    if (n < 0 || m < 0) return 0;
    return nCr(n + m, n);
}

/*************************************/
// 謎演算
/*************************************/

// gcdは関数__gcdを使いましょう。long long対応している。

// a x + b y = gcd(a, b)
long long extgcd(long long a, long long b, long long &x, long long &y) {
    long long g = a; x = 1; y = 0;
    if (b != 0) g = extgcd(b, a % b, y, x), y -= (a / b) * x;
    return g;
}


/*************************************/
// GF(p)の行列演算
/*************************************/
using number = Mod;
using arr = vector<number>;
using matrix = vector<vector<Mod>>;

ostream &operator<<(ostream &o, const arr &v) { rep(i, v.size()) cout << v[i] << " "; cout << endl; return o; }
ostream &operator<<(ostream &o, const matrix &v) { rep(i, v.size()) cout << v[i]; return o; }

matrix zero(int n) { return matrix(n, arr(n, 0)); } // O(n^2)
matrix identity(int n) { matrix A(n, arr(n, 0)); rep(i, n) A[i][i] = 1; return A; } // O(n^2)
// O(n^2)
arr mul(const matrix &A, const arr &x) { 
    arr y(A.size(), 0); 
    rep(i, A.size()) rep(j, A[0].size()) y[i] += A[i][j] * x[j]; 
    return y; 
} 
// O(n^3)
matrix mul(const matrix &A, const matrix &B) {
    matrix C(A.size(), arr(B[0].size(), 0));
    rep(i, C.size())
        rep(j, C[i].size())
        rep(k, A[i].size())
        C[i][j] += A[i][k] * B[k][j];
    return C;
}
// 構築付なし累乗
//
// O(n^3 log e)
matrix pow(const matrix &A, long long e) {
    return e == 0 ? identity(A.size())  :
        e % 2 == 0 ? pow(mul(A, A), e/2) : mul(A, pow(A, e-1));
}
// 構築付き累乗
//
// powA: A^2^i
// O(n^3 log e)
matrix pow(const vector<matrix>& powA, long long e) { // powA[0]がA
//    cout << powA[0] << "^" << e <<endl;
    if (e <= 0) return identity(powA[0].size());
    matrix ret = identity(powA[0].size());
    rep(i, powA.size()) if (e & (1ll << i)) {
        ret = mul(ret, powA[i]);
    }
    return ret;
}
arr powmul(const vector<matrix>& powA, long long e, arr& a) { // powA[0]がA
//    cout << powA[0] << "^" << e <<endl;
    if (e <= 0) return a;
    arr ret = a;
    rep(i, powA.size()) if (e & (1ll << i)) {
        ret = mul(powA[i], ret);
    }
    return ret;
}

// Aを最大e乗まで計算するためのpowAを構築する。
// powAは副作用で返す
//
// O(n^3 log e)
void construct_powA(const matrix &A, long long e, vector<matrix>& powA) {
    powA.clear();
    powA.push_back(A);
    for (int i = 1; (1ll << i) < e; i++) {
        powA.push_back(mul(powA[i-1], powA[i-1]));
    }
}


int main(void) {
    ll n, c; cin >> n >> c;
    vll a(n); rep(i, a.size()) cin >> a[i];

    matrix A = zero(n);
    rep(i, n) repi(j, i, n) A[j][i] = a[i];
    vector<matrix> powA;
    construct_powA(A, c+10, powA);

    arr x(n); rep(i, n) x[i] = 1;

    arr retvec = powmul(powA, c, x);

    Mod ret = retvec[n-1];
    rep(i, n) ret -= (Mod(a[i]) ^ c);
    cout << ret << endl;

    return 0;
}