#pragma GCC optimize ("O3")
#pragma GCC target ("avx")

#include <cstdio>
#include <cassert>
#include <cmath>
#include <cstring>

#include <iostream>
#include <algorithm>
#include <vector>
#include <map>
#include <set>
#include <functional>
#include <stack>
#include <queue>

#include <tuple>

#define getchar getchar_unlocked
#define putchar putchar_unlocked

#define _rep(_1, _2, _3, _4, name, ...) name
#define rep2(i, n) rep3(i, 0, n)
#define rep3(i, a, b) rep4(i, a, b, 1)
#define rep4(i, a, b, c) for (int i = int(a); i < int(b); i += int(c))
#define rep(...) _rep(__VA_ARGS__, rep4, rep3, rep2, _)(__VA_ARGS__)

using namespace std;

using i8 = signed char;
using i16 = signed short;
using i64 = long long;
using u8 = unsigned char;
using u32 = unsigned;
using u64 = unsigned long long;
using f80 = long double;

namespace poly_light {
  
using R = int;
using poly = vector<R>;

vector<i64> tmp64;
R mod;
i64 lmod;

R mul_mod(R a, R b) { return i64(a) * b % mod; }
i64 add_mod64(i64 a, i64 b) { return (a += b - lmod) < 0 ? a + lmod : a; }
i64 sub_mod64(i64 a, i64 b) { return (a -= b) < 0 ? a + lmod : a; }
R fixed(R a) { return (a %= mod) < 0 ? a + mod : a; }

void set_mod(R m) {
  mod = m;
  lmod = i64(mod) << 32;
}

poly poly_mul(const poly& f, const poly& g) {
  int s1 = f.size(), s2 = g.size(), s = s1 + s2 - 1;
  tmp64.assign(s, 0);
  rep(i, s1) if (f[i]) rep(j, s2) {
    tmp64[i + j] = add_mod64(tmp64[i + j], i64(f[i]) * g[j]);
  }
  poly ret(s);
  rep(i, s) ret[i] = tmp64[i] % mod;
  return ret;
}

poly poly_rem(const poly& f, const poly& g) {
  int s1 = f.size(), s2 = g.size();
  if (s1 < s2) return f;
  assert(g[0] == 1);
  tmp64.resize(s1);
  copy(f.begin(), f.end(), tmp64.begin());
  rep(i, s1 - s2 + 1) {
    int c = tmp64[i] % mod;
    if (c) rep(j, 1, s2) tmp64[i + j] = sub_mod64(tmp64[i + j], i64(c) * g[j]);
    tmp64[i] = c;
  }
  poly ret(s2 - 1);
  rep(i, s2 - 1) ret[i] = tmp64[s1 - s2 + 1 + i] % mod;
  return ret;
}

poly x_pow_mod(i64 e, const poly& f) {
  if (e == 0) return poly(1, 1);
  poly ret = poly_rem(poly({1, 0}), f);
  for (i64 mask = (i64(1) << __lg(e) >> 1); mask; mask >>= 1) {
    ret = poly_mul(ret, ret);
    if (e & mask) ret.push_back(0);
    ret = poly_rem(ret, f);
  }
  return ret;
}

R nth_term(i64 e, poly f, poly terms, const R mod) {
  if (mod == 1) return 0;
  assert(f.size() >= terms.size() + 1);
  set_mod(mod);
  rep(i, f.size()) f[i] = fixed(f[i]);
  rep(i, terms.size()) terms[i] = fixed(terms[i]);
  auto rem = x_pow_mod(e, f); reverse(rem.begin(), rem.end());
  i64 ret = 0;
  rep(i, rem.size()) ret = add_mod64(ret, i64(rem[i]) * terms[i]);
  return ret % mod;
}

} // poly_light

void solve() {
  const int mod = 1e9 + 7;
  poly_light::set_mod(mod);
  auto pow_mod = [&] (int b, i64 e) {
    int ret = 1;
    for (; e; e >>= 1, b = i64(b) * b % mod) if (e & 1) ret = i64(ret) * b % mod;
    return ret;
  };
  int A[128], sum[128];
  int n; i64 c;
  while (~scanf("%d %lld", &n, &c)) {
    poly_light::poly f(1, 1), terms(n, 0);
    int ans = 0;
    rep(i, n) {
      scanf("%d", &A[i]);
      f = poly_light::poly_mul(f, {1, (mod - A[i]) % mod});
      sum[i] = A[i];
      ans = (ans + pow_mod(A[i], c)) % mod;
    }
    rep(i, n) rep(j, n) (terms[i] += sum[j]) %= mod, sum[j] = (i64(terms[i]) * A[j]) % mod;
    ans = (mod - ans + poly_light::nth_term(c - 1, f, terms, mod)) % mod;
    printf("%d\n", ans);
  }
}

int main() {
  auto beg = clock();
  solve();
  auto end = clock();
  fprintf(stderr, "%.3f sec\n", double(end - beg) / CLOCKS_PER_SEC);
}