# Find all the numbers in the range which has prime set bits.

**Objective**: Given a range, find all the numbers in the range which has prime set bits.

**Example**:

L = 4, R = 10 Output: 5 Explanation: 4 = 1 0 0 ( not prime) 5 = 1 0 1 (prime) 6 = 1 1 0 (prime) 7 = 1 1 1 (prime) 8 = 1 0 0 0 ( not prime) 9 = 1 0 0 1 (prime) 10 = 1 1 0 0 (prime) Total 5 numbers which has prime set bits.

**Approach**:

- Iterate through all numbers from L to R
- For each number, count no of set bits.
- check if the count is a prime number, if yes add it to result.

**Time Complexity**: **O( N Sqrt (N) )**

This algorithm can be improved using **Sieve of Eratosthenes Algorithm. **We will implement that in our next article – ** **Numbers with prime set bits in a given range using Sieve of Eratosthenes Algorithm

**Complete Code:**

**Output:**

5