ref: c91479e8172bc493694e9c1e1d15e7eb867af6f8
dir: /sys/games/lib/sudoku/boards/hard-2005-05-01.su/
.362..17. 9.....2.. ...8.5... ....8.7.6 .5.....3. 3.4.7.... ...4.7... ..8.....7 .49..832. 836249175 915763248 472815693 291384756 657192834 384576912 163427589 528931467 749658321