This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A056785 #32 Aug 28 2025 11:13:58 %S A056785 1,4,23,211,2227,25824,310242,3818983,47752136,604425323 %N A056785 Number of polydominoes. %C A056785 From Vicher's table. %C A056785 This gives the number of polyominoes of order 2n that can be tiled by dominoes in at least one way. - _Joseph Myers_, Jun 10 2012 %H A056785 M. Keller, <a href="http://www.solitairelaboratory.com/polyenum.html">Counting Polyforms</a> %H A056785 Arthur O'Dwyer, <a href="https://quuxplusone.github.io/blog/2025/08/23/polybars/">Counting polybar polyominoes</a>, (2025). %H A056785 Herman Tulleken, <a href="https://www.researchgate.net/publication/333296614_Polyominoes">Polyominoes 2.2: How they fit together</a>, (2019). %H A056785 M. Vicher, <a href="http://www.vicher.cz/puzzle/polyforms.htm">Polyforms</a> %H A056785 <a href="/index/Do#domino">Index entries for sequences related to dominoes</a> %F A056785 a(n) + A213376(n) = A210996(n). - _R. J. Mathar_, Jan 30 2023 %Y A056785 Cf. A056786, A213376, A213377, A213378. %K A056785 hard,more,nonn,changed %O A056785 1,2 %A A056785 _James Sellers_, Aug 28 2000 %E A056785 Edited by _T. D. Noe_, Apr 09 2009 %E A056785 Offset corrected and a(6)-a(9) added by _Joseph Myers_, Jun 10 2012 %E A056785 a(10) added by _Arthur O'Dwyer_, Aug 28 2025