Solving Riddler Classic @ https://fivethirtyeight.com/features/can-you-hunt-for-the-mysterious-numbers/ with an ad-hoc method that improves significantly on brute force by generating and trying only the possible row numbers where the last digit can appear in the last column.
This takes advantage of the observation that the last column product is rather small and only 6 digits can appear in any of its acceptable factorizations.
The solution is found and checked as unique within a couple of seconds.