The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.



(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A056779 Number of poly-IH73-tiles (holes allowed) with n cells. 1


%S 1,1,3,7,21,60,208,704,2542,9192,34053,126771,476849,1802367,6851960,

%T 26152629

%N Number of poly-IH73-tiles (holes allowed) with n cells.

%C Originally from Vicher's table, which lists this as "Puzzle 3".

%C Isohedral tiling IH73 (see Figure 6.2.4 of Grünbaum and Shephard) is obtained from the regular square tiling by replacing the edges of each square by symmetric curves bulging alternately inwards and outwards, so that each modified square now has a rotation of order two and reflections in horizontal and vertical axes as symmetries but no longer has rotations of order four or diagonal reflections as symmetries. - Joseph Myers, Oct 08 2011

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

%H M. Keller, <a href="http://www.solitairelaboratory.com/polyenum.html">Counting Polyforms</a>

%H M. Vicher, <a href="http://www.vicher.cz/puzzle/polyforms.htm">Polyforms</a>

%K nonn,hard

%O 1,3

%A _James A. Sellers_, Aug 28 2000

%E Edited by _T. D. Noe_, Apr 09 2009

%E Edited and a(11)-a(16) by _Joseph Myers_, Oct 08 2011

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 7 00:22 EDT 2021. Contains 343609 sequences. (Running on oeis4.)