If you're still interested,
I confirmed that the puzzle was solvable, and now it's been reset. A hint for the current version of the puzzle is the answer starts with "2941682...". You can see the most recent correct solution I submitted by looking at this issue: https://github.com/strawstack/strawstack/issues/32 and you can see the previous puzzle by looking at the commit history of this repo: https://github.com/strawstack/strawstack
I can give more hints if needed. No one but me (the designer) has ever solved this before, but I feel that the puzzle mechanic is not too complex.