by dobrichev » Mon Aug 15, 2016 8:19 pm
Hi sekret and welcome to the forum.
Few questions
- What are the allowed operations over the small cubes? Is the rotation over any axis allowed? Does the orientation of the label matter? Is it possible to arrange a big cube having on the same surface, say, label "1" and next to it label "2" but rotated on 90 or 180 or 270 degrees?
- Is the central cube visible? Should every invisible internal plane of the big cube consist of labels 1-9 too?
Depending on the above details, some of the small cubes in your example can be considered equal, like these
19. cube: 1 4 7 1 4 7
22. cube: 4 7 1 4 7 1
25. cube: 7 1 4 7 1 4