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

const int N = 1e5+5;
const long long mod = 1e9+7;
long long a[N],prefixsum,reprefixsum,sum,f;

long long qpow(long long base,long long times){
	long long tot = 1;
	while(times){
		if(times & 1) tot = tot * base % mod;
		base = base * base % mod;
		times >>= 1;
	}
	return tot % mod;
}

int main(){
	int n,m;
	scanf("%d %d",&n,&m);
	for(int i = 1;i <= n;++ i){
		scanf("%d",&a[i]);
		prefixsum = (prefixsum + a[i] * (n - i + 1)) % mod;
		reprefixsum = (reprefixsum + a[i] * i) % mod;
		sum = (sum + a[i]) % mod;
	}
	long long s = qpow(2,m) - 1,f = (s + 1) * s / 2 % mod;
	long long base = f * n % mod * sum % mod;
	long long d = qpow(2,m - 1);
	long long use1 = (base + d * prefixsum % mod + d * reprefixsum % mod ) % mod;
	long long use2 = (base + d * 2 * prefixsum % mod) % mod;
	printf("%lld",max(use1,use2));
	return 0;
}