---
id: 5900f4741000cf542c50ff86
title: 'Problem 263: An engineers'' dream come true'
challengeType: 5
forumTopicId: 301912
dashedName: problem-263-an-engineers-dream-come-true
---

# --description--

Consider the number 6. The divisors of 6 are: 1,2,3 and 6.

Every number from 1 up to and including 6 can be written as a sum of distinct divisors of 6:

1=1, 2=2, 3=1+2, 4=1+3, 5=2+3, 6=6.

A number n is called a practical number if every number from 1 up to and including n can be expressed as a sum of distinct divisors of n.

A pair of consecutive prime numbers with a difference of six is called a sexy pair (since "sex" is the Latin word for "six"). The first sexy pair is (23, 29).

We may occasionally find a triple-pair, which means three consecutive sexy prime pairs, such that the second member of each pair is the first member of the next pair.

We shall call a number n such that : (n-9, n-3), (n-3,n+3), (n+3, n+9) form a triple-pair, and the numbers n-8, n-4, n, n+4 and n+8 are all practical,

an engineers’ paradise.

Find the sum of the first four engineers’ paradises.

# --hints--

`euler263()` should return 2039506520.

```js
assert.strictEqual(euler263(), 2039506520);
```

# --seed--

## --seed-contents--

```js
function euler263() {

  return true;
}

euler263();
```

# --solutions--

```js
// solution required
```
