Find the 444th Prime number converted to hexadecimal which contains the word "beef"

beefprime.php

<?php
	set_time_limit(0);	
	function isPrime($number) {
		$sqrt = ceil(sqrt($number));
		if ($number <= 1) {
			return FALSE;
		} else if ($number <= 3) {
			return TRUE;
		} else if ( !($number % 2) || !($number % 3) ) {
			return FALSE;
		}
		
		for($i = 3; $i <= $sqrt; $i = $i+2) {
			if (!($number % $i)) {
				return FALSE;
			}
		}
		return TRUE;
	}

	function findString($occurrence=1, $string='beef') {
		$i = 1;
		$current = 0;
		while (TRUE) {
			if (strpos(dechex($i), $string) !== FALSE && isPrime($i) === TRUE) {
				$current++;
				if ($current === $occurrence) {
					return $i;
				}
			}
			$i++;
		}
	}
	//find first prime with beef
	$beef = findString();
	var_dump($beef, dechex($beef));
	//find 444th prime with beef
	$beef = findString(444);
	var_dump($beef, dechex($beef));
?>