sub uniqRands {
    state $vec = '';
    $vec = '' if @_ == 2;
    my $n;
    1 while vec( $vec, $n = int( rand $_[0] ), 1 );
    vec( $vec, $n, 1 ) = 1;
    return $n;
}

my @sample = map uniqRands( 100_000 ), 1 .. 30;