freeCodeCamp/curriculum/challenges/english/10-coding-interview-prep/project-euler/problem-188-the-hyperexponentiation-of-a-number.md

---
id: 5900f4291000cf542c50ff3b
challengeType: 5
title: 'Problem 188: The hyperexponentiation of a number'
forumTopicId: 301824
---

## Description
<section id='description'>
The hyperexponentiation or tetration of a number a by a positive integer b, denoted by a↑↑b or ba, is recursively defined by:
a↑↑1 = a,
a↑↑(k+1) = a(a↑↑k).

Thus we have e.g. 3↑↑2 = 33 = 27, hence 3↑↑3 = 327 = 7625597484987 and 3↑↑4 is roughly 103.6383346400240996*10^12.
Find the last 8 digits of 1777↑↑1855.
</section>

## Instructions
<section id='instructions'>

</section>

## Tests
<section id='tests'>

```yml
tests:
  - text: <code>euler188()</code> should return 95962097.
    testString: assert.strictEqual(euler188(), 95962097);

```

</section>

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

<div id='js-seed'>

```js
function euler188() {

  return true;
}

euler188();
```

</div>



</section>

## Solution
<section id='solution'>

```js
// solution required
```

</section>