ref: fbf9f131b5931defb02ff08d54d1e088d9f51a15
dir: /sys/games/lib/sudoku/boards/easy-2005-03-11.su/
9.5.7...1 ...52.9.. 7....9..3 ..4.9..32 ..6...8.. 27..3.6.. 5..2....8 ..2.47... 1...6.7.9 965374281 438521976 721689543 854796132 316452897 279138654 597213468 682947315 143865729