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 A240121 #12 Apr 16 2014 18:32:15 %S A240121 0,0,0,1,0,13,5,183,75,4408,1501,180324 %N A240121 Number of inequivalent ways to cut an n X n square into squares with integer sides, such that the dissection has two reflective symmetries in axes parallel to the sides, and no other reflective symmetries. %C A240121 The two reflective symmetries imply 180-degree (but not 90-degree) rotational symmetry. %H A240121 Ed Wynn, <a href="http://arxiv.org/abs/1308.5420">Exhaustive generation of Mrs Perkins's quilt square dissections for low orders</a>, arXiv:1308.5420 %e A240121 This dissection is the only example for n=4: %e A240121 --------- %e A240121 | | | | %e A240121 --- --- %e A240121 | | | | %e A240121 --------- %e A240121 | | | | %e A240121 --- --- %e A240121 | | | | %e A240121 --------- %Y A240121 Cf. A226979, A045846, A224239, A240120, A240122. %K A240121 nonn,more %O A240121 1,6 %A A240121 _Ed Wynn_, Apr 01 2014