sub iter {
    my @factors = @_;
    my $str;

    return sub {
        if (not defined $str) {
            $str =  "1" . ("0" x $#factors);
            return map { substr($str, $_, 1) ? $factors[$_] : () }
                   0 .. $#factors;
        }
        for ($str) {
            s/0(0*)$/1$1/
              or s/11$/01/
              or s/^(.*)10(.*)$/"${1}01" . "0" x length $2/e
              or return;
        }

        return map { substr($str, $_, 1) ? $factors[$_] : () }
               0 .. $#factors;
    };
}   

my $i = iter( 2, 3, 5, 7 );
while (my @s = $i->()) {
    print "@s\n";
}

__END__
2
2 3
2 3 5
2 3 5 7
2 3 7
2 5
2 5 7
2 7
3
3 5
3 5 7
3 7
5
5 7
7