A197552 Number of free poly-IH19-tiles (holes allowed) with n cells.

1, 1, 4, 10, 36, 146, 631, 2815, 12987, 60601, 286376, 1364399, 6546220, 31585133

Offset: 1

Author

Joseph Myers, Oct 16 2011

Keywords

• hard
• nonn

Comments

Equivalently, polyhexes where two polyhexes are considered equivalent if and only if they are related by a translation, a rotation of order 3 or a reflection or glide reflection in a line parallel to the sides of the hexagons.

References

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

Crossrefs

Cf. A000228, A001207, A006535, A057973, A197549, A197550, A197551, A197553, A197554.