#include <bits/stdc++.h>
using namespace std;
const long long mx = 10000007;
using pii = pair<long long, long long>;
const long long mod = 1e9 + 7;
const double pi = acos(-1);
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  ;
  long long t;
  cin >> t;
  while (t--) {
    long long n;
    cin >> n;
    vector<pii> v;
    vector<long long> ev, od;
    set<long long> s;
    for (long long i = 0; i < n; i++) {
      s.insert(i + 1);
      if ((i + 1) % 2 == 0)
        ev.push_back(i + 1);
      else
        od.push_back(i + 1);
    }
    if (n == 2) {
      cout << 2 << endl;
      cout << 1 << " " << 2 << endl;
      continue;
    }
    sort(ev.begin(), ev.end());
    sort(od.begin(), od.end());
    reverse(ev.begin(), ev.end());
    reverse(od.begin(), od.end());
    long long d;
    if (n % 2 == 0) {
      d = ev[0];
      s.erase(d);
      long long i = 1, j = 0;
      while (1) {
        if (d % 2 == 0) {
          long long a = d;
          long long b = ev[i];
          s.erase(b);
          v.push_back({a, b});
          d = (a + b) / 2;
          if (s.size() == 0) break;
          i++;
          if (i > ev.size()) break;
        } else {
          long long a = d;
          long long b = od[j];
          s.erase(b);
          v.push_back({a, b});
          j++;
          d = (a + b) / 2;
          if (s.size() == 0) break;
          if (j > od.size()) break;
        }
        if (s.size() == 0) break;
      }
    } else if (n % 2 == 1) {
      d = od[0];
      s.erase(d);
      long long i = 1, j = 0;
      while (1) {
        if (d % 2 == 1) {
          long long a = d;
          long long b = od[i];
          s.erase(b);
          v.push_back({a, b});
          d = (a + b) / 2;
          if (s.size() == 0) break;
          i++;
          if (i > od.size()) break;
        } else {
          long long a = d;
          long long b = ev[j];
          s.erase(b);
          v.push_back({a, b});
          j++;
          d = (a + b) / 2;
          if (s.size() == 0) break;
          if (j > ev.size()) break;
        }
        if (s.size() == 0) break;
      }
    }
    cout << d << endl;
    for (long long i = 0; i < v.size(); i++) {
      cout << v[i].first << " " << v[i].second << endl;
    }
  }
  return 0;
}
