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 A153243 #4 Jul 21 2017 12:36:32 %S A153243 0,1,6,42,43,51,52,385,386,387,388,389,413,414,415,416,417,475,476, %T A153243 477,478,479,503,504,505,506,507,551,552,553,554,555,4089,4090,4091, %U A153243 4092,4093,4094,4095,4096,4097,4098,4099,4100,4101,4102,4179,4180 %N A153243 Positions of balanced binary trees in A014486, i.e., trees where number of vertices in the right subtree = number of vertices in the left subtree. %Y A153243 Positions of zeros in A153239. %K A153243 nonn %O A153243 0,3 %A A153243 _Antti Karttunen_, Dec 21 2008