Nice attempt DannyHamilton! There must be a way to make it much more efficient as the last three addresses were found so fast it couldn't have been by brute forcing.
Maybe if we learn a bit more from how the numbers were generated it could greatly optimize the program.
"7" and "8" are close together as well. Even if the numbers are created randomly is not that unreasonable to assume that a few numbers in the series are close together.
@Danny does the tool you wrote/modified support using a GPU by any chance? I would suspect thats the only way to get to 50+ bit within a reasonable amount of time. If we assume similar performance to vanitygen, we can expect 30-40 million keys per modern GPU.
Shorena, I think you have a gtx 970? If so, that would be a faster way of making the program which cracks the keys quicker however, this depends on whether the program supports the cracking via a gpu...
How much of a faster process would it be? 200%?