MathDB
64 grids

Source: China North MO

August 14, 2006
rotationcombinatorics unsolvedcombinatorics

Problem Statement

Can we put positive integers 1,2,3,641,2,3, \cdots 64 into 8×88 \times 8 grids such that the sum of the numbers in any 44 grids that have the form like TT ( 33 on top and 11 under the middle one on the top, this can be rotate to any direction) can be divided by 55?