3v4l.org

run code in 300+ PHP versions simultaneously
<?php function isPrime($num) { for ($i = 2; $i < $num; $i++) { if ($num % $i == 0) { return false; } } return true; } function firstAndLastDigitEqual($num, $digit) { return substr($num, 0, 1) == (string)$digit && substr($num, -1) == (string)$digit; } $foundPrimes = 0; for ($i = 1; true; $i++) { if (firstAndLastDigitEqual($i, 3) && isPrime($i)) { if (++$foundPrimes == 333) { echo $i; break; } } }
Output for 5.2.1, 5.3.0 - 5.3.5, 5.3.7, 5.3.9, 5.3.11 - 5.3.15, 5.3.17 - 5.3.27, 5.4.0 - 5.4.20, 5.5.0 - 5.5.4, 7.1.25, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
302443
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0, 5.2.2 - 5.2.17, 5.3.6, 5.3.8, 5.3.10, 5.3.16

Process exited with code 137.
preferences:
211.5 ms | 403 KiB | 266 Q