freeCodeCamp/curriculum/challenges/chinese/10-coding-interview-prep/project-euler/problem-468-smooth-divisors-of-binomial-coefficients.md

---
id: 5900f5411000cf542c510054
title: 'Problem 468: Smooth divisors of binomial coefficients'
challengeType: 5
forumTopicId: 302143
dashedName: problem-468-smooth-divisors-of-binomial-coefficients
---

# --description--

An integer is called B-smooth if none of its prime factors is greater than B.

Let SB(n) be the largest B-smooth divisor of n. Examples: S1(10) = 1 S4(2100) = 12 S17(2496144) = 5712

Define F(n) = ∑1≤B≤n ∑0≤r≤n SB(C(n,r)). Here, C(n,r) denotes the binomial coefficient. Examples: F(11) = 3132 F(1 111) mod 1 000 000 993 = 706036312 F(111 111) mod 1 000 000 993 = 22156169

Find F(11 111 111) mod 1 000 000 993.

# --hints--

`euler468()` should return 852950321.

```js
assert.strictEqual(euler468(), 852950321);
```

# --seed--

## --seed-contents--

```js
function euler468() {

  return true;
}

euler468();
```

# --solutions--

```js
// solution required
```