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 A226454 #24 Jul 05 2013 04:24:43 %S A226454 1,2,4,8,16,30,54,98,180,332,612,1120,2046,3736 %N A226454 The number of squares added in the n-th step of a Pythagoras tree of the 30-60-90 triangle. %C A226454 Growth of the Pythagoras tree based on the triangle with internal angles of 30, 60 and 90 degrees. %C A226454 The generating rule is expansion in sequential order on each stage; the smaller squares (opposite to the 30 deg angle) come first. The generating order labeled by "stage-number" starts as 1-1; 2-1, 2-2; 3-1, 3-2, 3-3, 3-4;...and so on. Overlap is prohibited, i.e., if any part of a new element in the next generating order cuts into any previous (existing, lower order) one, that new elements will be not be inserted/added: lower generating orders have precedence over higher generating orders. %C A226454 The non-overlap rule limits the growth of the sequence to a(n+1) <= 2*a(n). %C A226454 For Pythagoras tree based on isosceles right triangle with the same rule, the sequence will be A053599(n-1) + 1. %H A226454 Kival Ngaokrajang, <a href="/A226454/a226454.jpg">Pythagoras tree by isosceles right triangle for n = 1..12</a> %H A226454 Kival Ngaokrajang, <a href="/A226454/a226454_1.jpg">Pythagoras tree by 30-60-90 triangle for n = 1..11</a> %H A226454 Wikipedia, <a href="http://en.wikipedia.org/wiki/Pythagoras_tree_(fractal)">Pythagoras tree</a> %Y A226454 Cf. A053599. %K A226454 nonn %O A226454 1,2 %A A226454 _Kival Ngaokrajang_, Jun 07 2013