//84104971101048411497 - Can you guess what does this mean?
using namespace std;
#include <bits/stdc++.h>
#define mapii map<int, int>
#define debug(a) cout << #a << ": " << a << endl
#define debuga1(a, l, r) fto(i, l, r) cout << a[i] << " "; cout << endl
#define fdto(i,  r, l) for(int i = (r); i >= (l); --i)
#define fto(i, l, r) for(int i = (l); i <= (r); ++i)
#define forit(it, var) for(__typeof(var.begin()) it = var.begin(); it != var.end(); it++)
#define forrit(rit, var) for(__typeof(var.rbegin()) rit = var.rbegin(); rit != var.rend(); rit++)
#define ii pair<int, int>
#define iii pair<int, ii>
#define ff first
#define ss second
#define mp make_pair
#define pb push_back
#define ll long long
#define maxN 1000005
#define oo 1000000007
#define sz(a) (int)a.size()

template <class T>
T min(T a, T b, T c) {
    return min(a, min(b, c));
}

template <class T>
T max(T a, T b, T c) {
    return max(a, max(b, c));
}

int q, d[maxN], id[maxN], cnt;
vector<int> ver[maxN], adj[maxN];

void Infix(int u) {
    if (adj[u].size() > 0) Infix(adj[u][0]);
    id[u] = ++cnt;
    if (adj[u].size() > 1) Infix(adj[u][1]);    
}

void Prefix(int u) {
    printf("%d ", id[u]);
    forit(it, adj[u]) Prefix(*it);
}

int main () {
    scanf("%d", &q);
    fto(i, 1, q) {
        int n; ll c;
        scanf("%d%lld", &n, &c);
        
        fto(i, 0, n-1) d[i] = n-i-1, c -= d[i];
        
        int cur = 1, minD = 1;
        fto(i, 0, n-1) {            
            int x = max(0, min((int)min((ll)n, -c), d[i]-minD));
            d[i] -= x; c += x;
            ++cur;
            if (cur == 1<<minD) cur = 1, ++minD;
        }
        //fto(i, 0, n-1) printf("%d ", d[i]);
        //puts("");
        if (c != 0) puts("-1");
        else {
            cnt = 0;
            fto(i, 0, n-1) ver[i].clear(), adj[i].clear();
            
                        
            fto(i, 0, n-1) ver[d[i]].pb(i);
            fdto(i, n-1, 1) {
                fto(j, 0, sz(ver[i])-1) adj[ver[i-1][j/2]].pb(ver[i][j]);
            }
            Infix(ver[0][0]);
            Prefix(ver[0][0]);
            puts("");
        }
    }

    return 0;
}