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


#include<atcoder/modint>
using mint = atcoder::modint998244353;

const int mx = 2<<17;
mint fac[mx+1],ifac[mx+1];
int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    int t;
    cin>>t;
    while(t--){
        int n,m;
        cin>>m>>n;
        vector<vector<mint>> dp(n+1,vector<mint>(3,0));
        dp[0][0] = 1;
        for(int i = 0;i<n;i++){
            dp[i+1][0] += dp[i][0] + dp[i][1] + dp[i][2];
            if(m>3){
                mint tmp = mint(m) * mint(m-1) / mint(2);
                tmp -= m;
                dp[i+1][2] += tmp * dp[i][0];
                tmp = mint(m-1) * mint(m-2) / mint(2);
                tmp -= m - 2;
                dp[i+1][2] += tmp * dp[i][1];
                tmp = mint(m-2) * mint(m-3) / mint(2);
                tmp -= m - 4;
                dp[i+1][2] += tmp * dp[i][2];
            }
            dp[i+1][1] += mint(m) * dp[i][0];
            dp[i+1][1] += mint(m-1) * dp[i][1];
            dp[i+1][1] += mint(m-2) * dp[i][2];
        }
        mint ans = dp[n][0] + dp[n][1] + dp[n][2];
        cout<<ans.val()<<endl;
    }
}