write a go solution for Description:
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.

Input Format:
The first line contains a single integer t (1<=t<=10^4) — the number of test cases.

The first and only line of each test case contains two integers n and k (2<=n<=10^9; 1<=k<=10^9).

Output Format:
For each test case, print one integer — the k-th special number in increasing order modulo 10^9+7.

Note:
For n=3 the sequence is [1,3,4,9...]. Output only the code with no comments, explanation, or additional text.