user
Task

pi(n), the number of primes <= n, where **pi(n) < 22**

Also see
:   * Prime-counting\_function.
    * Tables and hints   by Tomás Oliveira e Silva.
    * the OEIS entry:   A0000720 pi(n), the number of primes <= n. Sometimes called PrimePi(n)....
assistant
```
my @pi = (1..*).map: { state $pi = 0; $pi += .is-prime };

say @pi[^(@pi.first: * >= 22, :k)].batch(10)».fmt('%2d').join: "\n";

```

Output:

```
 0  1  2  2  3  3  4  4  4  4
 5  5  6  6  6  6  7  7  8  8
 8  8  9  9  9  9  9  9 10 10
11 11 11 11 11 11 12 12 12 12
13 13 14 14 14 14 15 15 15 15
15 15 16 16 16 16 16 16 17 17
18 18 18 18 18 18 19 19 19 19
20 20 21 21 21 21 21 21
```