m{
  (?{ [ {}, 0 ] })
  ^
  \d*?
  (\d+)
  (?(?{
    length($1) > (length($_) - $-[1])/2
    or $^R->[0]{$1}++
  })(?!))
  (?{ [ $^R->[0], 1 ] })
  (?>
    (?: \d*? \1 (?{ [ $^R->[0], $^R->[1] + 1 ] }) )+
    (?{ print report($1, $^R->[1]) })
  )
  (?!)
}x;

sub report {
  my ($str, $count) = @_;
  sprintf "length: %d digits: %s quantity: %d\n",
    length($str), $str, $count;
}