A366338 Number of free (4,2)-polyominoids with n cells, allowing right-angled (or hard) connections only.

1, 1, 8, 44, 509, 7091

Offset: 1

Author

Pontus von Brömssen, Oct 07 2023

Keywords

• nonn
• hard
• more

Comments

Two squares sharing an edge have a right-angled connection if they do not lie in the same plane.

Connections that are not right-angled (flat connections) may occur, but the polyominoids considered here must be connected through right-angled connections only.

Links

• Wikipedia, Polyominoid.
• Index entries for sequences related to polyominoes.

Crossrefs

45th row of A366766.

Cf. A075679, A365654, A366334, A366339 (fixed), A366340.