#include "bits/stdc++.h"
using namespace std;
#define rep(i,n) for(int (i)=0;(i)<(int)(n);++(i))
#define rer(i,l,u) for(int (i)=(int)(l);(i)<=(int)(u);++(i))
#define reu(i,l,u) for(int (i)=(int)(l);(i)<(int)(u);++(i))
static const int INF = 0x3f3f3f3f; static const long long INFL = 0x3f3f3f3f3f3f3f3fLL;
typedef vector<int> vi; typedef pair<int, int> pii; typedef vector<pair<int, int> > vpii; typedef long long ll;
template<typename T, typename U> static void amin(T &x, U y) { if (y < x) x = y; }
template<typename T, typename U> static void amax(T &x, U y) { if (x < y) x = y; }

int main() {
	int T;
	scanf("%d", &T);
	for (int ii = 0; ii < T; ++ ii) {
		int N; int C;
		scanf("%d%d", &N, &C);
		vector<ll> lo(N + 1), up(N + 1);
		rer(n, 2, N)
			lo[n] = (n - 1) + lo[(n - 1) / 2] + lo[n / 2];
		rer(n, 2, N)
			up[n] = (n - 1) + up[n - 1];
		if (C < lo[N] || up[N] < C) {
			puts("-1");
			continue;
		}
		vector<int> ans(N, -1);
		int num = 1;
		function<void(int,int,int)> solve = [&](int left, int right, int k) {
			int n = right - left;
			if (n == 0)
				return;
			if (n == 1) {
				ans[left] = num ++;
				return;
			}
			assert(lo[n] <= k && k <= up[n]);
			k -= n - 1;
			rep(i, n) {
				if (lo[i] + lo[n - 1 - i] <= k) {
					int l = (int)min(up[i], k - lo[n - 1 - i]);
					solve(left + 1, left + 1 + i, l);
					ans[left] = num ++;
					solve(left + 1 + i, right, k - l);
					return;
				}
			}
			assert(false);
		};
		solve(0, N, C);
		for (int i = 0; i < (int)ans.size(); ++ i) {
			if (i != 0) putchar(' ');
			printf("%d", ans[i]);
		}
		puts("");
	}
	return 0;
}