B. Special Numbers
bitmasks; math
Theofanis really likes sequences of positive integers, thus his teacher (Yeltsa Kcir) gave him a problem about a sequence that consists of only special numbers.Let's call a positive number special if it can be written as a sum of different non-negative powers of \(n\). For example, for \(n = 4\) number \(17\) is special, because it can be written as \(4^0 + 4^2 = 1 + 16 = 17\), but \(9\) is not.Theofanis asks you to help him find the \(k\)-th special number if they are sorted in increasing order. Since this number may be too large, output it modulo \(10^9+7\).
The first line contains a single integer \(t\) (\(1 \le t \le 10^4\)) — the number of test cases.The first and only line of each test case contains two integers \(n\) and \(k\) (\(2 \le n \le 10^9\); \(1 \le k \le 10^9\)).
For each test case, print one integer — the \(k\)-th special number in increasing order modulo \(10^9+7\).
For \(n = 3\) the sequence is \([1,3,4,9...]\)