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

# --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.

# --hints--

`euler188()` should return 95962097.

```js
assert.strictEqual(euler188(), 95962097);
```

# --seed--

## --seed-contents--

```js
function euler188() {

  return true;
}

euler188();
```

# --solutions--

```js
// solution required
```