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 A308563 #11 Jul 01 2019 16:38:37 %S A308563 0,4,8,18,130,2206,4326,4650,16344,16814,47942,48000,49928 %N A308563 Langton's ant on a three-dimensional grid: iterations where the ant passes through the origin. %C A308563 For the rules applying to this ant, see A325953. %C A308563 The sequence is finite, with 49928 being the last term. The ant never reaches the origin again after that, since it starts building a highway pattern at iteration 93475. %H A308563 Charlie Neder, <a href="/A308563/a308563.py.txt">Python program for generating this sequence</a> %Y A308563 Cf. A102358, A325953, A325954, A325955. %K A308563 nonn,fini,full %O A308563 1,2 %A A308563 _Felix Fröhlich_ and _Charlie Neder_, Jun 07 2019