I had thought of that - but 170 Mb would be okay for all my machines - one compromise might be to store say 5 digits (10P5) with a simple array of the remaining 5 being referenced as the value, e.g.:

$hash{ '01234' } = \( 5..9 );
[download]

This would reduce the storage by a factor of more than a hundred, while requiring that the last half of the digits would then need to be compared with the array being also pre-stored at each outer node of the hash, but with the same 120x performance for those last digits as compared with processing 10 without prestored results -- total performance improvement should be around 80x in this case (but PLUS the fixed overheads if you don't have linux shared memory to pre-store the solution)