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 A151526 #9 Dec 05 2014 03:03:00 %S A151526 1,2,4,8,19,43,103,239,569,1339,3185,7503,17794,41908,99137,233251, %T A151526 550624,1294032,3049412,7158698,16844717,39505579,92841149 %N A151526 Number of strip poly-IH64-tiles (holes allowed) with n cells. %C A151526 Equivalently, strip polyominoes where two polyominoes are considered the same if and only if they are related by a translation or a reflection in a horizontal line. Formerly described as one-sided strip polyrects, but that is A151523. %D A151526 Branko Grünbaum and G. C. Shephard, Tilings and Patterns. W. H. Freeman, New York, 1987, Sections 6.2 and 9.4. %Y A151526 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 A151526 nonn %O A151526 1,2 %A A151526 _Ed Pegg Jr_, May 13 2009 %E A151526 Edited and a(15)-a(23) by _Joseph Myers_, Nov 24 2010