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 A151523 #8 Feb 16 2025 08:33:09 %S A151523 1,2,4,10,20,48,106,252,578,1372,3208,7584,17850,42102,99276,233716, %T A151523 550960,1295146,3050226,7161346,16846668,39511876,92845830 %N A151523 Number of 1-sided strip polyrhombs with n cells. %C A151523 Also counts 1-sided strip polyrects. %H A151523 Ed Pegg, Jr., <a href="http://demonstrations.wolfram.com/PolyformExplorer/">Illustrations of polyforms</a> %H A151523 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Polyrhomb.html">Polyrhomb</a> %H A151523 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Polyrect.html">Polyrect</a> %Y A151523 Strip polyominoes by group of symmetries relating shapes considered the same: A002013 (all symmetries), A182644 (translations only), A151514 (rotations and translations), A151527 (horizontal and vertical reflections, rotations of order 2 and translations), A151524 (reflections in either diagonal, rotations of order 2 and translations), A151523 (rotations of order 2 and translations), A151526 (reflections in a horizontal line and translations), A182646 (reflections in a NE-SW diagonal line and translations) %K A151523 nonn,hard,more %O A151523 1,2 %A A151523 _Ed Pegg Jr_, May 13 2009 %E A151523 Edited and a(15)-a(23) by _Joseph Myers_, Nov 24 2010