freeCodeCamp/curriculum/challenges/english/10-coding-interview-prep/project-euler/problem-206-concealed-square.md

---
id: 5900f43a1000cf542c50ff4d
title: 'Problem 206: Concealed Square'
challengeType: 5
forumTopicId: 301847
dashedName: problem-206-concealed-square
---

# --description--

Find the unique positive integer whose square has the form 1_2_3_4_5_6_7_8_9_0, where each “\_” is a single digit.

# --hints--

`euler206()` should return 1389019170.

```js
assert.strictEqual(euler206(), 1389019170);
```

# --seed--

## --seed-contents--

```js
function euler206() {

  return true;
}

euler206();
```

# --solutions--

```js
// solution required
```