> For the complete documentation index, see [llms.txt](https://trizen.gitbook.io/sidef-lang/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://trizen.gitbook.io/sidef-lang/programming_tasks/a/anti-primes.md).

# Anti-primes

Using the built-in *Number.sigma0* method to count the number of divisors.

```ruby
say with (0) {|max|
    1..Inf -> lazy.grep { (.sigma0 > max) && (max = .sigma0) }.first(20)
}
```

## Output:

```
[1, 2, 4, 6, 12, 24, 36, 48, 60, 120, 180, 240, 360, 720, 840, 1260, 1680, 2520, 5040, 7560]
```