OFFSET
1,3
COMMENTS
Two cubes sharing a face have a right-angled connection if they do not lie in the same 3-dimensional affine subspace.
Connections that are not right-angled (flat connections) may occur, but the polyominoids considered here must be connected through right-angled connections only.
Also, number of free polysticks in 4 dimensions with right-angled connections.
LINKS
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
Pontus von Brömssen, Oct 07 2023
STATUS
approved