freeCodeCamp/curriculum/challenges/chinese/10-coding-interview-prep/project-euler/problem-393-migrating-ants.md

---
id: 5900f4f61000cf542c510008
title: 'Problem 393: Migrating ants'
challengeType: 5
forumTopicId: 302058
dashedName: problem-393-migrating-ants
---

# --description--

An n×n grid of squares contains n2 ants, one ant per square.

All ants decide to move simultaneously to an adjacent square (usually 4 possibilities, except for ants on the edge of the grid or at the corners).

We define f(n) to be the number of ways this can happen without any ants ending on the same square and without any two ants crossing the same edge between two squares.

You are given that f(4) = 88. Find f(10).

# --hints--

`euler393()` should return 112398351350823100.

```js
assert.strictEqual(euler393(), 112398351350823100);
```

# --seed--

## --seed-contents--

```js
function euler393() {

  return true;
}

euler393();
```

# --solutions--

```js
// solution required
```