freeCodeCamp/curriculum/challenges/english/08-coding-interview-prep/project-euler/problem-351-hexagonal-orchards.english.md

---
id: 5900f4cb1000cf542c50ffde
challengeType: 5
title: 'Problem 351: Hexagonal orchards'
---

## Description
<section id='description'>
A hexagonal orchard of order n is a triangular lattice made up of points within a regular hexagon with side n. The following is an example of a hexagonal orchard of order 5:






Highlighted in green are the points which are hidden from the center by a point closer to it. It can be seen that for a hexagonal orchard of order 5, 30 points are hidden from the center.



Let H(n) be the number of points hidden from the center in a hexagonal orchard of order n.



H(5) = 30. H(10) = 138. H(1 000) = 1177848.



Find H(100 000 000).
</section>

## Instructions
<section id='instructions'>

</section>

## Tests
<section id='tests'>

```yml
tests:
  - text: <code>euler351()</code> should return 11762187201804552.
    testString: 'assert.strictEqual(euler351(), 11762187201804552, "<code>euler351()</code> should return 11762187201804552.");'

```

</section>

## Challenge Seed
<section id='challengeSeed'>

<div id='js-seed'>

```js
function euler351() {
  // Good luck!
  return true;
}

euler351();
```

</div>



</section>

## Solution
<section id='solution'>

```js
// solution required
```
</section>