#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
ll mod=1000000007;
int n,m;
const int N=1e5+5;
int a[N];
int main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	cin>>n>>m;
	ll ab=0,ba=0,sum=0;
	for(int i=1;i<=n;i++) {cin>>a[i];
	sum+=a[i];sum%=mod;
	ab+=i*a[i];ab%=mod;
	ba+=(n-i+1)*a[i];ba%=mod;
	}
	//cout<<ab<<" "<<ba<<" "<<sum<<endl;
	ll ans=0,ans1=0,ans2=0;
	ll shu=1;
	for(int i=1;i<=m;i++){
		if(i==m) {
			ans1=((ab+ba)%mod*shu)%mod;
			ans=sum*shu%mod;
		}
		shu*=2;
		shu%=mod;
		if(i==m) {
			ans=(ans*(shu-1))%mod;
		}
	}
	ans=(ans*n)%mod;
	ans2=(ba*shu)%mod;
	//cout<<ans<<" "<<ans1<<" "<<ans2<<endl;
	ans1=(ans+ans1)%mod;
	ans2=(ans2+ans)%mod;
	cout<<max(ans1,ans2)<<endl;
	return 0;
}