---
id: 5900f4291000cf542c50ff3a
title: 'Problem 187: Semiprimes'
challengeType: 1
forumTopicId: 301823
dashedName: problem-187-semiprimes
---

# --description--

A composite is a number containing at least two prime factors. For example, $15 = 3 × 5; 9 = 3 × 3; 12 = 2 × 2 × 3$.

There are ten composites below thirty containing precisely two, not necessarily distinct, prime factors: 4, 6, 9, 10, 14, 15, 21, 22, 25, 26.

How many composite integers, $n &lt; {10}^8$, have precisely two, not necessarily distinct, prime factors?

# --hints--

`semiPrimes()` should return `17427258`.

```js
assert.strictEqual(semiPrimes(), 17427258);
```

# --seed--

## --seed-contents--

```js
function semiPrimes() {

  return true;
}

semiPrimes();
```

# --solutions--

```js
// solution required
```
