#include <bits/stdc++.h>
using namespace std;
#define debug(fmt, ...) \
  fprintf(stderr, "[%d] " fmt "\n", __LINE__, ##__VA_ARGS__)
template <class _Tx, class _Ty>
inline void chkmin(_Tx& x, const _Ty& y) { if (y < x) x = y; }
template <class _Tx, class _Ty>
inline void chkmax(_Tx& x, const _Ty& y) { if (x < y) x = y; }
bool Mbe;
using ll = long long;
constexpr int N = 2e5 + 10;
int n, c;
vector<ll> dp[N];
ll calc(int c, int k, int l, int r) {
  ll val = (ll)k * c * (c - 1) / 2 - (ll)k * (k - 1) / 2 * (c + 1) + k - 1;
  int x1 = max(l, min(r, k - 2)), x2 = max(l, min(r, k - 1));
  return val + max((ll)x1 * (k - 1) - (ll)x1 * (x1 + 1) / 2,
                   (ll)x2 * (k - 1) - (ll)x2 * (x2 + 1) / 2);
}
void mian() {
  cin >> n >> c;
  int mxk = (n + 2) / (c + 1);
  ll ans = dp[c][mxk];
  if (mxk * (c + 1) - 2 < n)
    chkmax(ans, calc(c, mxk + 1, (mxk + 1) * (c + 1) - 2 - n, c - 1));
  cout << (ll)n * (n + 1) / 2 + ans << '\n';
}
bool Med;
int main() {
  // debug("Mem: %.4lfMB.", fabs(&Med - &Mbe) / 1048576);
  cin.tie(0)->sync_with_stdio(0);
  int cas;
  cin >> cas;
  for (int c = 1; c < N; ++c) {
    dp[c].resize(N / (c + 1) + 1);
    for (int k = 0; k * (c + 1) < N; ++k) {
      dp[c][k] = calc(c, k, 0, c - 1);
      if (k) chkmax(dp[c][k], dp[c][k - 1]);
    }
  }
  while (cas--) mian();
  return 0;
}
/*
g++ -std=c++14 -O2 -o qoj-6823 qoj-6823.cpp -Wall -Wextra
-Wshadow -fsanitize=address,undefined -g
*/