Problem of the Week 1145
Place the digits from 1 to 6 in the squares so that each row consists of six different numbers, each column consists of six different numbers, and the digit sum in each region is the same.
Note the absence of the condition that the digits in each region are distinct.
Source: G. Butters, F. Henle, J. Henle, C. McGaughey. Creating clueless puzzles, The Mathematical Intelligencer, 33:3 (2011) 102-105.
© Copyright 2011 Stan Wagon. Reproduced with permission.