#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using mint = modint998244353;
int main(){
  int N, K;
  cin >> N >> K;
  vector<int>a(N);
  for(int i=0;i<N;i++)cin >> a[i];
  vector<vector<mint>>F(N+1,vector<mint>(K+1,0));
  for(int i=0;i<=K;i++)F[0][i] = 1;
  for(int i=0;i<N;i++){
      for(int j=0;j<=K;j++){
          F[i+1][j]+=F[i][j]*(1<<j);
      }
      for(int j=1;j<=K;j++)F[i+1][j]+=F[i+1][j-1];
  }

  vector<vector<mint>>dp(N+1,vector<mint>(K+1,0));
  vector<vector<mint>>rdp(N+1,vector<mint>(K+1,0));

  for(int i=0;i<N;i++){
    mint ai = 1, rai = 1;
    for(int j=0;j<=K;j++){
      dp[i+1][j]+=(dp[i][j]+F[i][j]*ai)*(1<<j);
      rdp[i+1][j]+=(rdp[i][j]+F[i][j]*rai)*(1<<j);

      ai *= a[i];
      rai *= a[N-1-i];
    }

    for(int j=1;j<=K;j++){
      dp[i+1][j]+=dp[i+1][j-1];
      rdp[i+1][j]+=rdp[i+1][j-1];
    }
  }

  mint ans = 0;
  for(int i=2;i<=N;i++){
    ans += dp[i-2][K]*(1<<(2*K))*F[N-i][K-1];
    ans += F[i-2][K]*(1<<(2*K))*F[N-i][K-1]*(mint(a[i-1]).pow(K)+mint(a[i-2]).pow(K));
    ans += F[i-2][K]*(1<<(2*K))*rdp[N-i][K-1];
  }
  ans *= mint(4).pow(K).inv();
  cout << ans.val() << endl;



  return 0;
}