A270862 Number of polycubes with n cells, allowing edge connections as well as face connections, distinguishing mirror images.

1, 2, 9, 88, 1103, 17570, 295506, 5168034, 92436673

Offset: 1

Author

George Sicherman, Mar 24 2016

Keywords

• nonn
• nice
• more
• hard

Examples

			a(3)=9 because there are 8 ways to join 3 cells in the cubic grid at faces or edges, identifying reflections, and one of those 8 has distinct mirror images, which makes 9.
		

References

• Jørgen Lou, Danish Patent 126840 (27 August 1973).

Links

• G. L. Sicherman, Catalogue of Polykedges.

Crossrefs

Cf. A268666 (identifying mirror images), A000162, A030222 (2-dimensional polyplets).

Extensions

Terms a(8) and a(9) from Joerg Arndt and Márk Péter Légrádi, May 20 2023