freeCodeCamp/curriculum/challenges/chinese/10-coding-interview-prep/project-euler/problem-351-hexagonal-orchards.md

---
id: 5900f4cb1000cf542c50ffde
title: 'Problem 351: Hexagonal orchards'
challengeType: 5
forumTopicId: 302011
dashedName: problem-351-hexagonal-orchards
---

# --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).

# --hints--

`euler351()` should return 11762187201804552.

```js
assert.strictEqual(euler351(), 11762187201804552);
```

# --seed--

## --seed-contents--

```js
function euler351() {

  return true;
}

euler351();
```

# --solutions--

```js
// solution required
```