Randmon Uniques

use strict;
use warnings;
use Data::Dumper;

my $MAX_INT = 2 ** 16;

sub rand_boundary {
    my ($min, $max) = @_;
    my @possible_values = ($min .. $max);
    return $possible_values[ int(rand(@possible_values)) ];
}

sub rand_uniq {
    my $n = shift;
    my @integers = (0 .. $MAX_INT);

    for (my $i=0; $i<$n; $i++) {
        my $rand = rand_boundary($i, scalar(@integers) - 1);

        my $value = $integers[$rand];
        $integers[$rand] = $integers[$i];
        $integers[$i]   = $value;

        print "$value\n";
    }
}

rand_uniq($ARGV[0]);