A197550 Number of free poly-IH8-tiles (holes allowed) with n cells.

1, 3, 7, 28, 99, 433, 1852, 8463, 38798, 181889, 858570, 4093739, 19636172, 94759074, 459431326, 2237102027, 10933138191

Offset

1,2

Comments

Equivalently, one-sided polybricks, or polyhexes where two polyhexes are considered equivalent if and only if they are related by a translation or a rotation of order 2.

References

Branko Grünbaum and G. C. Shephard, Tilings and Patterns. W. H. Freeman, New York, 1987, Sections 6.2 and 9.4.

Links

Table of n, a(n) for n=1..17.

Tom McLean, IH8.

Crossrefs

Cf. A000228, A001207, A006535, A057973, A197549, A197551, A197552, A197553, A197554.

Sequence in context: A393000 A197960 A197959 * A289605 A361360 A296533

Adjacent sequences: A197547 A197548 A197549 * A197551 A197552 A197553

Keyword

hard,nonn,more

Author

Joseph Myers, Oct 16 2011

Extensions

a(15)-a(17) from John Mason, Jan 30 2026

Status

approved