#include <bits/stdc++.h>

//using namespace std;

using ll = long long;
using LL = unsigned long long;
using i128 = __int128;
constexpr int N = 1E5 + 10;
constexpr int mod = 1E9 + 7;
using std::cin;
using std::cout;
using std::vector;
using std::cerr;
using std::pair;


LL p[N] = {};

int init = []() {
    p[0] = 1;
    for (int i = 1; i < N; i++) {
        p[i] = (p[i - 1] + p[i - 1]) % mod;
    }
    return 0;
}();

int main() {
    cin.tie(nullptr) -> sync_with_stdio(false);
    int n, m;
    cin >> n >> m;

    auto norm = [&](LL x) {
        if (x < 0) x += mod;
        if (x >= mod) x-= mod;
        return x;
    };

    LL sum = 0;
    auto get = [&](vector<int> &a) {
        LL s = 0, now = 0;
        for (int i = 1; i <= n; i++) {
            now += a[i];
            s += now;
        }
        vector<LL> f(m + 1);
        f[0] = s % mod;
        for (int i = 1; i <= m; i++) {
            f[i] = norm(norm(f[i - 1] + f[i - 1]) + sum * p[i - 1] % mod * p[i - 1] % mod * n % mod);
        }
        return pair(s, f);
    };

    vector<int> a(n + 1);
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
        sum += a[i];
    }

    auto [s1, f] = get(a);
//    for (int i = 0; i <= m; i++) {
//        cout << f[i] << " \n"[i == m];
//    }
    reverse(a.begin() + 1, a.end());
    auto [s2, g] = get(a);
//    for (int i = 0; i <= m; i++) {
//        cout << g[i] << " \n"[i == m];
//    }
    if (s1 > s2) {
        cout << f[m] << "\n";
    } else {
        cout << norm(norm(f[m - 1] + g[m - 1]) + sum * p[m - 1] % mod * n % mod * p[m - 1] % mod);
    }

    return 0;
}