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 A217152 #12 Jun 21 2019 09:56:40 %S A217152 0,0,0,0,0,0,0,0,0,0,0,0,1,9,46,191,781,3161,15002 %N A217152 Number of nontrivially compound perfect squared rectangles of order n up to symmetries of the rectangle and its subrectangles. %C A217152 A squared rectangle (which may be a square) is a rectangle dissected into a finite number, two or more, of squares. If no two of these squares have the same size the squared rectangle is perfect. The order of a squared rectangle is the number of constituent squares. %C A217152 A squared rectangle is simple if it does not contain a smaller squared rectangle, compound if it does, and trivially compound if a constituent square has the same side length as a side of the squared rectangle under consideration. %H A217152 I. Gambini, <a href="http://alain.colmerauer.free.fr/alcol/ArchivesPublications/Gambini/carres.pdf">Quant aux carrés carrelés</a>, Thesis, Université de la Méditerranée Aix-Marseille II, 1999, p. 24. [But symmetries of subrectangles counted as distinct.] %H A217152 <a href="/index/Sq#squared_rectangles">Index entries for squared rectangles</a> %H A217152 <a href="/index/Sq#squared_squares">Index entries for squared squares</a> %Y A217152 Cf. A217153 (counts symmetries of subrectangles as distinct). %Y A217152 Cf. A002839, A110148, A181340, A217154, A217155. %K A217152 nonn,hard,more %O A217152 1,14 %A A217152 _Geoffrey H. Morley_, Sep 27 2012 %E A217152 a(18) and a(19) added by _Geoffrey H. Morley_, Oct 12 2012