#include<bits/stdc++.h>
using namespace std;
#define ll long long int
const ll mod = 1000000007;
int main()
{
  ll t;
  cin >> t;
  while(t--) {
      ll n, k;
      cin >> n >> k;
      vector<ll> a(n + 1);
      ll idx, x = 1;
      a[1] = x;
      x++;
      for(ll i = 2; i <= n; i++) {
          if(k > 0) {
              if((x + 1) <= n) {
                  a[i] = x + 1;
                  a[i + 1] = x;
                  i++;
                  x += 2;
                  k--;
              }
              else {
                  a[i] = x;
                  x++;
              }
          }
          else {
              a[i] = x;
              x++;
          }
      }
      if(k) {
          cout << -1 << endl;
      }
      else {
          for(ll i = 1; i <= n; i++) {
              cout << a[i] << " ";
          }
          cout << endl;
      }
  }
}