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 A274370 #19 Oct 11 2017 18:00:38 %S A274370 0,1,1,0,0,-1,-1,0,0,-1,-1,-2,-2,-1,-1,0,0,-1,-1,-2,-2,-3,-3,-2,-2,-1, %T A274370 -1,-2,-2,-1,-1,-2,-2,-1,-1,0,0,-1,-1,0,0,1,1,0,0,-1,-1,0,0,1,1,0,0,1, %U A274370 1,2,2,1,1,0,0,1,1,2,2,3,3,2,2,1,1,2,2,1,1,2 %N A274370 Let the starting square of Langton's ant have coordinates (0, 0), with the ant looking in negative x-direction. a(n) is the y-coordinate of the ant after n moves. %H A274370 Rémy Sigrist, <a href="/A274370/b274370.txt">Table of n, a(n) for n = 0..15000</a> %H A274370 Felix Fröhlich, <a href="/A274369/a274369.pdf">Coordinates of Langton's ant</a>. %H A274370 Wikipedia, <a href="https://en.wikipedia.org/wiki/Langton%27s_ant">Langton's ant</a>. %F A274370 a(n+104) = a(n) - 2 for n > 9975. - _Andrey Zabolotskiy_, Jul 05 2016 %Y A274370 Cf. A274369 (x-coordinate). %Y A274370 Cf. A102358, A102369, A204810, A255938, A261990, A269757. %K A274370 sign,look %O A274370 0,12 %A A274370 _Felix Fröhlich_, Jun 19 2016