$re = '/^ # Start of the string (or line with m/multiline flag)
(?=.*\d) # Lookahead that checks for at least one digit in the match
\+? # An optional literal plus \'+\'
[#*\d]{1,15} # one to fifteen of literal \'#\' or \'*\' or digit (\d is [0-9])
$ # End of the string (line with m/multiline flag)/mx';
$str = '+1234
445678999
+#7897897
+345764756#775
+#
+*';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php