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 A121197 #23 May 25 2025 05:33:23 %S A121197 2,2,8,34,158,777,4006,21224,114348,624222,3441050,19121530,106957272 %N A121197 Consider the tiling of the plane with squares of two different sizes as in Fig. 2.4.2(g) of Grünbaum and Shephard, p. 74. a(n) is the number of connected figures that can be formed on this tiling, from any n squares. %C A121197 The Zucca web site calls these figures "n-DifferentSquares". %C A121197 Also the number of one-sided polyforms on the faces of the truncated square tiling. - _Peter Kagey_, May 24 2025 %D A121197 Branko Grünbaum and G. C. Shephard, Tilings and Patterns. W. H. Freeman, New York, 1987. %H A121197 Peter Kagey, <a href="/A121197/a121197.pdf">Illustration of a(5)=158</a>. %H A121197 Livio Zucca, <a href="http://www.iread.it/lz/polymultiforms2.html">PolyMultiForms</a> %Y A121197 Cf. A121195, A121196, A121198, A343577. %K A121197 nonn,nice,hard,more %O A121197 1,1 %A A121197 _N. J. A. Sloane_, Aug 17 2006 %E A121197 More terms from _Don Reble_, Aug 17 2007 %E A121197 a(13) from _Joseph Myers_, Oct 06 2011