Print N of First Prime Number

#! /usr/bin/php
<?php
function isPrime($num){
    if( $num < 2 ) return false;
    for( $i=2;$i<=$num**0.5;++$i )
        if( !($num%$i) ) return false;
    return true;
}
function printFirstNPrime($N, $start = 2, $count = 0){
    if( $count == $N ) return;
    if( isPrime($start) ){
        ++$count;
        echo $start . ' ';
    }
    printFirstNPrime($N, ++$start, $count);
}
//kalau printFirstNPrime(1); cuma munculin 2
//kalau printFirstNPrime(2); cuma munculin 2 3
//kalau printFirstNPrime(3); cuma munculin 2 3 5
//kalau printFirstNPrime(4); cuma munculin 2 3 5 7
//kalau printFirstNPrime(5); cuma munculin 2 3 5 7 11
printFirstNPrime(5);