Comment by fjfaase
It would be nice, if they could publish the exact cover. I have written some algorithm that can estimate the number of solutions to an exact cover base on the number of solutions it found and the size of the 'tree' that has been explored.
I could write a program myself to calculate the exact cover, but I guess, it will take me about a day to do so. It would not surprise me if the exact cover will be a few hundred mega bytes (when using one character per position).
We haven't actually run the thing to completion. We ran it for a couple days and then stopped after finding tens of thousands of solutions. Might explore again if we have time to improve the solver efficiency.