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 A293540 #12 Oct 13 2017 03:22:13 %S A293540 0,0,1,1,0,-1,-1,0,1,2,2,1,-1,-2,-2,-1,1,2,2,-1,-1,0,3,3,2,1,0,-2,-2, %T A293540 -1,0,3,4,4,3,-1,-2,-3,-3,-2,0,1,1,-2,-2,-1,2,4,5,5,4,0,-2,-3,-3,1,1, %U A293540 0,-4,-4,-3,2,2,1,0,-1,-4,-4,-3,-3,-4,-4,2,2,1,0 %N A293540 Let P be the sequence of distinct lattice points defined by the following rules: P(1) = (0,0), P(2) = (1,0), and for any n > 2, P(n) is the closest lattice point to P(n-1) such that the angle of the vectors (P(n-2), P(n-1)) and (P(n-1), P(n)), say t, satisfies 0 < t <= Pi/2, and in case of a tie, minimize the angle t; a(n) = Y-coordinate of P(n). %C A293540 See A293539 for the X-coordinate of P(n), and additional comments. %H A293540 Rémy Sigrist, <a href="/A293540/b293540.txt">Table of n, a(n) for n = 1..12000</a> %H A293540 Rémy Sigrist, <a href="/A293540/a293540.gp.txt">PARI program for A293540</a> %F A293540 a(n + 258) = a(n) - 8 for any n >= 9118. %o A293540 (PARI) See Links section. %Y A293540 Cf. A293539. %K A293540 sign,look %O A293540 1,10 %A A293540 _Rémy Sigrist_, Oct 11 2017