freeCodeCamp/curriculum/challenges/english/10-coding-interview-prep/project-euler/problem-148-exploring-pascals-triangle.english.md

---
id: 5900f4021000cf542c50ff14
challengeType: 5
isHidden: false
title: 'Problem 148: Exploring Pascal''s triangle'
forumTopicId: 301777
---

## Description
<section id='description'>
We can easily verify that none of the entries in the first seven rows of Pascal's triangle are divisible by 7:

<pre>
            1
          1   1
        1   2   1
      1   3   3   1
    1   4   6   4   1
  1   5   10  10  5   1
1   6   15  20  15  6   1
</pre>
However, if we check the first one hundred rows, we will find that only 2361 of the 5050 entries are not divisible by 7.
</section>

## Instructions
<section id='instructions'>
Find the number of entries which are not divisible by 7 in the first one billion (10<sup>9</sup>) rows of Pascal's triangle.
</section>

## Tests
<section id='tests'>

```yml
tests:
  - text: <code>euler148()</code> should return 2129970655314432.
    testString: assert.strictEqual(euler148(), 2129970655314432);

```

</section>

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

<div id='js-seed'>

```js
function euler148() {
  // Good luck!
  return true;
}

euler148();
```

</div>



</section>

## Solution
<section id='solution'>

```js
// solution required
```

</section>