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

#define MAX 128

double R[2*MAX][MAX][MAX];
int B[2*MAX][MAX][MAX];
int n;

double f(int c0, int c1, int c2)
{
    if(c0 < 0 || c1 < 0 || c2 < 0) return 0;
    double &res = R[c0][c1][c2];
    if(B[c0][c1][c2] != 0) return res;
    B[c0][c1][c2] = 1;

    int a = c0*(c0 - 1);
    int b = 4*c0*c1;
    int c = 4*c0*c2;
    int d = 4*c1*(c1 - 1);
    int e = 8*c1*c2;
    int g = 2*c2*(2*c2 - 1);
    int t = n*n;
    if(a + b + c + d + e + g == 0) return res;
    return res = (t 
            + a*f(c0 - 2, c1 + 1, c2) 
            + b*f(c0 - 1, c1 - 1, c2 + 1) 
            + c*f(c0 - 1, c1, c2)
            + d*f(c0, c1 - 2, c2 + 1)
            + e*f(c0, c1 - 1, c2)
            + g*f(c0, c1, c2 - 1)
        )/(a + b + c + d + e + g + 0.0);
}

long long sum(long long s)
{
    return s*(s + 1)/2;
}

void solve(int test)
{
    long long s, c;
    cin >> s >> c;
    long long res = 0;
    int ss = s;
    if(s > sum(c)) s = sum(c);
    long long t = (s + c)/(c + 1);
    while(s > t*c)
    {
        s = t*c;
        t = (s + c)/(c + 1);
    }
    res = sum(ss) - sum(s);
    res += c*(t*s - (c + 1)*sum(t - 1));
    cout << res << endl;
}

int main()
{
    int t = 1;
    cin >> t;
    for(int i = 0; i < t; ++i)
        solve(i);
    return 0;
}