题库练习 Coprime Subsequences
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A10875 | Coprime Subsequences

时间限制1s
内存限制256MB
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题目描述

Let's call a non-empty sequence of positive integers $a_{1},a_{2}...\ a_{k}$ coprime if the greatest common divisor of all elements of this sequence is equal to $1$ .

Given an array $a$ consisting of $n$ positive integers, find the number of its coprime subsequences. Since the answer may be very large, print it modulo $10^{9}+7$ .

Note that two subsequences are considered different if chosen indices are different. For example, in the array $[1,1]$ there are $3$ different subsequences: $[1]$ , $[1]$ and $[1,1]$ .

输入格式

The first line contains one integer number $n$ ( $1<=n<=100000$ ).

The second line contains $n$ integer numbers $a_{1},a_{2}...\ a_{n}$ ( $1<=a_{i}<=100000$ ).

输出格式

Print the number of coprime subsequences of $a$ modulo $10^{9}+7$ .

输入输出样例

输入 #1
3
1 2 3
输出 #1
5
输入 #2
4
1 1 1 1
输出 #2
15
输入 #3
7
1 3 5 15 3 105 35
输出 #3
100
C++ 编辑器
输入
输出