freeCodeCamp/curriculum/challenges/english/08-coding-interview-prep/project-euler/problem-326-modulo-summations.english.md

---
id: 5900f4b21000cf542c50ffc5
challengeType: 5
title: 'Problem 326: Modulo Summations'
---

## Description
<section id='description'>
Let an be a sequence recursively defined by: .


So the first 10 elements of an are: 1,1,0,3,0,3,5,4,1,9.

Let f(N,M) represent the number of pairs (p,q) such that:


It can be seen that f(10,10)=4 with the pairs (3,3), (5,5), (7,9) and (9,10).


You are also given that f(104,103)=97158.

Find f(1012,106).
</section>

## Instructions
<section id='instructions'>

</section>

## Tests
<section id='tests'>

```yml
tests:
  - text: <code>euler326()</code> should return 1966666166408794400.
    testString: assert.strictEqual(euler326(), 1966666166408794400, '<code>euler326()</code> should return 1966666166408794400.');

```

</section>

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

<div id='js-seed'>

```js
function euler326() {
  // Good luck!
  return true;
}

euler326();
```

</div>



</section>

## Solution
<section id='solution'>

```js
// solution required
```
</section>