#include<bits/stdc++.h>
using namespace std;
#define FOR(i,s,t) for(int i=(s),_t=(t); i<=_t; ++i)
#define DOR(i,s,t) for(int i=(s),_t=(t); i>=_t; --i)
typedef double db;
typedef long long ll;
const int N=500000+50;
const int Mod=998244353;
const ll INF=1e17;
struct node {
    int b,k,l;
    ll v;
    ll value() const{
        ll x=0;
        FOR(i,1,l) {
            x=x*b+k;
            if(x>=INF) return INF;
        }
        return x;
    }
    db Log() const {
        return log(k)-log(b-1)+l*log(b);
    }
};
int cmp(node a,node b) {
    ll va=a.value(),vb=b.value();
    if(va<INF || vb<INF) {
        return va<vb?-1:va>vb;
    }
    db la=a.Log(),lb=b.Log();
    if(fabs(la-lb)<1e-9 && a.v==b.v) return 0;
    return la<lb?-1:la>lb;
}
bool operator <(node a,node b) {
    return cmp(a,b)>0;
}
ll solve(int n) {
    if(!n) return 0;
    priority_queue<node> Q;
    FOR(b,2,16) {
        FOR(k,1,b-1) {
            Q.push({b,k,1,k});
        }
    }
    ll res=0;
    node las={0,0,0};
    int m=0;
    while(m<n) {
        auto x=Q.top();
        // cerr << x.b << ' ' << x.k << ' ' << x.l << ' ' << x.v << endl;
        Q.pop();
        if(las.b==0 || cmp(las,x)!=0) {
            res=(res+x.v)%Mod;
            ++m;
        }
        las=x;
        Q.push({x.b,x.k,x.l+1,(x.v*x.b+x.k)%Mod});
    }
    return res;
}
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int T;
    cin >> T;
    while(T--) {
        int l,r;
        cin >> l >> r;
        ll res=(solve(r)-solve(l-1))%Mod;
        if(res<0) res+=Mod;
        cout << res << '\n';
    }
    return 0;
}