ref: 9ef4ba83f62761b517db23a16e2f61e5861aae23
dir: /sys/games/lib/sudoku/boards/medium-2005-03-31.su/
....38... .76...... 28..9.... .6.8...43 8.16.39.5 79...1.2. ....8..92 ......43. ...95.... 159238764 376415289 284796351 562879143 841623975 793541826 617384592 925167438 438952617