2019-06-11 目次：Sudoku hard, The guardian を Mathematica で解く- 2019 Sudoku 目次へ Sudoku-4401-hard, the guardian, 25 May, 2019 - 数独を Mathematica で解く Sudoku-4560-hard, the guardian, 4 Oct, 2019 - 数独を Mathematica で解く 目次へ