#include<bits/stdc++.h>
namespace {
#pragma GCC diagnostic ignored "-Wunused-function"
#include<atcoder/all>
#pragma GCC diagnostic warning "-Wunused-function"
using namespace std;
using namespace atcoder;
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
#define rrep(i,n) for(int i = (int)(n) - 1; i >= 0; i--)
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
template<class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } else return false; }
template<class T> bool chmin(T& a, const T& b) { if (b < a) { a = b; return true; } else return false; }
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;
using mint = modint998244353;

constexpr int FACT_SIZE = 1000000;
mint Fact[FACT_SIZE + 1];
mint iFact[FACT_SIZE + 1];
const auto fact_init = [] {
    Fact[0] = mint::raw(1);
    for(int i = 1; i <= FACT_SIZE; ++i) {
        Fact[i] = Fact[i-1] * i;
    }
    iFact[FACT_SIZE] = Fact[FACT_SIZE].inv();
    for(int i = FACT_SIZE; i; --i) {
        iFact[i-1] = iFact[i] * i;
    }
    return false;
}();

mint comb(int n, int k) {
    if (k == 0) return mint::raw(1);
    assert(n >= 0 && k >= 0);
    if (k > n) return mint::raw(0);
    return Fact[n] * iFact[n - k] * iFact[k];
}

mint icomb(int n, int k) {
    return iFact[n] * Fact[n - k] * Fact[k];
}

mint fact(int n) {return Fact[n];}
mint perm(int n, int k) {
    assert(0 <= n);
    return Fact[n] * iFact[n - k];
}

template<class T, T (*add)(T, T), T (*zero)(), T (*mul)(T, T), T (*one)(), int N>
struct Mat : array<array<T, N>, N> {
  using M = Mat<T, add, zero, mul, one, N>;
  void make_identity() {
    for (int i = 0; i < N; i++) {
      for (int j = 0; j < N; j++) {
        (*this)[i][j] = zero();
      }
    }
    for (int i = 0; i < N; i++) {
      (*this)[i][i] = one();
    }
  }
  M& operator+=(const M& rhs) {
    for (int i = 0; i < N; i++) {
      for (int j = 0; j < N; j++) {
        (*this)[i][j] = add((*this)[i][j], rhs[i][j]);
      }
    }
    return *this;
  }
  M& operator*=(const M& rhs) {
    static M temp;
    for (int i = 0; i < N; i++) {
      for (int j = 0; j < N; j++) {
        temp[i][j] = zero();
      }
    }
    for (int i = 0; i < N; i++) {
      for (int j = 0; j < N; j++) {
        for (int k = 0; k < N; k++) {
          temp[i][k] = add(temp[i][k], mul((*this)[i][j], rhs[j][k]));
        }
      }
    }
    *this = temp;
    return *this;
  }
  template <class I>
  void inplace_pow(I k) {
    assert(k >= 0);
    static M temp;
    temp = *this;
    make_identity();
    while (k) {
      if (k & 1) *this *= temp;
      k >>= 1;
      if (k) temp *= temp;
    }
  }
  friend ostream& operator<<(ostream& os, const M& A) {
    for (int i = 0; i < N; i++) {
      for (int j = 0; j < N; j++) {
        os << A[i][j] << " \n"[j + 1 == N];
      }
    }
    return os;
  }
};


mint add(mint x, mint y) { return x + y; }
mint zero() { return mint(); }
mint mul(mint x, mint y) { return x * y; }
mint one() { return mint::raw(1); }
using M = Mat<mint, add, zero, mul, one, 3>;

} int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int tt;
  cin >> tt;
  while(tt--) {
    int m, n;
    cin >> m >> n;
    M a;
    a[0] = {1, m, m >= 4 ? m * ll(m - 3) / 2 : 0LL};
    a[1] = {1, m - 1, m >= 4 ? (m * ll(m - 3) - 2 * (m - 3)) / 2 : 0LL};
    a[2] = {1, m - 2, m >= 4 ? (m * ll(m - 3) - 2 * 2 * (m - 3) + 2) / 2 : 0LL};
    a.inplace_pow(n);
    mint ans;
    rep(j, 3) ans += a[0][j];
    cout << ans.val() << '\n';
  }
}