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 A169788 #6 Nov 25 2018 13:50:32 %S A169788 0,0,0,1,1,4,6,7,7,14,20,25,27,30,36,37,37,52,66,79,89,100,112,117, %T A169788 115,122,140,153,157,158,168,167,167,198,228,257,283,310,338,359,373, %U A169788 396,428,453,467,474,486,491,481,496,538,575,603,628,654,665,653,650,680,707,711 %N A169788 a(n) = n(n+1)/2 - A169780(n). %C A169788 If n is a power of 2, this is the number of OFF cells after n stages in a 60-degree wedge of the hexagonal CA (see A170905, A169780, A151723, A169789). %H A169788 N. J. A. Sloane, <a href="/A169788/b169788.txt">Table of n, a(n) for n = 0..1025</a> %Y A169788 Cf. A170905, A169780, A151723, A169789. %K A169788 nonn %O A169788 0,6 %A A169788 _N. J. A. Sloane_, May 13 2010