#include <bits/stdc++.h>
#define rep(i,a,b) for(int i=(a);i<(b);++i)
using namespace std;
using pii = pair<int,int>;
using ll = long long;
using pll = pair<ll,ll>;
using vi = vector<int>;
 
using ld = long double;
 
#define all(x) (x).begin(), (x).end()
 
const int maxn = 1e6+10, inf = 1e9+100;
const ll linf = 1e18+100;
const int mod = 998244353;
 
const ld eps = 1e-9;
const ld PI = acos(-1.L);


vector<ll> ans;
pii cst[17];

ll modpow(ll a,ll b){
  ll ans =1;
  for(a%=mod;b;b>>=1,a=a*a%mod)if(b&1)ans=ans*a%mod;
  return ans;
}
ll inv(ll x){return modpow(x,mod-2);}
ll iva[17];
ll modeval(ll base, pii st) {
  return (modpow(base, st.first + 1) - 1) * iva[base - 1] % mod * st.second % mod;
}

ll smeval(ll base, pii st) {
  ll ans = 0;
  for(ll p = st.second, i = 0; i <= st.first; i++) {
    if(i != 0) p *= base;
    ans += p;
  }
  return ans;
}

ld lga[17];
ld apeval(ll base, pii st) {
  return lga[base] * (st.first + 1) - lga[base - 1] + lga[st.second];
}

void solvee(){
  ll l, r;
  cin >> l >> r;
  ll res = (ans[r] - ans[l-1]) % mod;
  if(res < 0) res += mod;
  cout << res << "\n";
}

void solve(){
  ans.push_back(0);
  for(int i=2;i<=16;i++){
    cst[i] = {0,1};
    iva[i] = inv(i);
    lga[i] = log((ld)i);
  }
  iva[1] = 1;
  lga[1] = 0;
  using T = pair<ld,int>;
  priority_queue<T,vector<T>,greater<T>> pq;
  for(int i=2;i<=16;i++)pq.push({(ld)0,i});
  bool small = true;
  ll lv = -1;
  ld lfv = -1;
  while(ans.size() < maxn) {
    auto [val, base] = pq.top();
    pq.pop();
    // cerr << val << " " << base << " " << cst[base].first << " " << cst[base].second << endl;
    if(val > log((ld)linf)) small = false;
    if(small) {
      ll ev = smeval(base, cst[base]);
      // cerr << ev << endl;
      assert(lv <= ev);
      if(ev != lv) {
        lv = ev;
        ans.push_back(modeval(base,cst[base]));
        // cerr << "NEW " << ans.back() << endl;
      }
    }
    else {
      if(abs(val-lfv) > eps) {
        lfv = val;
        ans.push_back(modeval(base,cst[base]));
        // cerr << "NEW " << ans.back() << endl;
      }
    }
    cst[base].second ++;
    if(cst[base].second == base) {
      cst[base].first ++;
      cst[base].second = 1;
    }
    ld v = apeval(base,cst[base]);
    if(v <= log((ld)linf)) {
      v = log((ld)smeval(base,cst[base]));
    }
    pq.push({v,base});
  }
  // for(int i=1;i<=1000;i++) cerr << ans[i] << endl;
  for(int i=1;i<ans.size();i++)ans[i] = (ans[i-1] + ans[i]) % mod;

  int tc;
  cin >> tc;
  while(tc--){
    solvee();
  }
}
 
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout<<fixed;
  cout.precision(20);
  cerr << fixed;
  cerr.precision(5);
  solve();
}