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 A099733 #7 Aug 04 2020 13:38:28
%S A099733 0,4,12,0,24,8,12,0,52,8,12,0,4,8,0,56,72,40,60,0,52,24,92,48,28,96,
%T A099733 312,40
%N A099733 a(n) is the number of active cells after a solid n X n square has reached a static state or constant population, closed and infinite loop in Conway's Game of Life.
%C A099733 Starting population for n is n^2.
%C A099733 a(n)=0 for n={1,4,8,12,15,20,..?..}, meaning that after a particular, finite number of generations, the grid is forever empty.
%C A099733 a(n) reaches a nonempty, single static state after a particular, finite number of generations for n={2,5,6,10,13,14,16,18,22,24,26,27,28,..?..}.
%C A099733 a(n) enters a constant population, infinite, two-state and closed loop after a particular, finite number of generations for n={3,7,9,11,17,19,21,23,25,..?..}.
%C A099733 For even generations > 153, a(29)=128. For odd generations > 153, a(29)=120. n=29 is the first value of a(n) for which the system enters a two-state loop with variable population after a particular, finite number of generations.
%H A099733 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/GameofLife.html">Game of Life</a>
%e A099733 a(5)=24 because a 5 X 5 solid square placed on an otherwise empty grid at generation 0 in Conway's Game of Life will enter a static state at generation 11 with 24 cells forever alive/active/on.
%K A099733 nonn,more
%O A099733 1,2
%A A099733 Joseph Biberstine (jrbibers(AT)indiana.edu), Nov 08 2004