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 A182646 #8 Dec 05 2014 03:03:12 %S A182646 1,1,4,7,19,41,104,235,572,1331,3193,7485,17811,41867,99181,233157, %T A182646 550718,1293817,3049649,7158201,16845217,39504435,92842398 %N A182646 Number of strip poly-IH68-tiles (holes allowed) with n cells. %C A182646 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 NE-SW diagonal line. %D A182646 Branko Grünbaum and G. C. Shephard, Tilings and Patterns. W. H. Freeman, New York, 1987, Sections 6.2 and 9.4. %Y A182646 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 A182646 nonn %O A182646 1,3 %A A182646 _Joseph Myers_, Nov 24 2010