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 A240120 #15 Apr 16 2014 18:31:24 %S A240120 0,0,0,1,1,9,19,121,275,2489,7217,86775 %N A240120 Number of inequivalent ways to cut an n X n square into squares with integer sides, such that the dissection has reflective symmetry in both diagonals and no other reflective symmetries. %C A240120 'Inequivalent' has the same sense as in A224239: we do not regard dissections that differ by a rotation and/or reflection as distinct. %C A240120 The two reflective symmetries imply 180-degree (but not 90-degree) rotational symmetry. %H A240120 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 A240120 This is the single dissection for n=4: %e A240120 --------- %e A240120 | | | | %e A240120 | ----- %e A240120 | | | | %e A240120 --------- %e A240120 | | | | %e A240120 ----- | %e A240120 | | | | %e A240120 --------- %Y A240120 Cf. A226979, A045846, A224239, A240121, A240122. %K A240120 nonn,more %O A240120 1,6 %A A240120 _Ed Wynn_, Apr 01 2014