---
id: 5900f48f1000cf542c50ffa2
challengeType: 5
title: 'Problem 291: Panaitopol Primes'
forumTopicId: 301943
---
## Description
A prime number p is called a Panaitopol prime if for some positive integersx and y.
Find how many Panaitopol primes are less than 5×1015.
## Instructions
## Tests
```yml
tests:
- text: euler291() should return 4037526.
testString: assert.strictEqual(euler291(), 4037526);
```
## Challenge Seed
```js
function euler291() {
// Good luck!
return true;
}
euler291();
```