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 A359216 #36 Apr 01 2023 11:22:41 %S A359216 0,1,1,0,0,-1,-1,-2,-2,-1,-1,0,0,1,1,2,2,3,3,2,2,1,1,0,0,-1,-1,-2,-2, %T A359216 -3,-3,-4,-4,-3,-3,-2,-2,-1,-1,0,0,1,1,2,2,3,3,4,4,5,5,4,4,3,3,2,2,1, %U A359216 1,0,0,-1,-1,-2,-2,-3,-3,-4,-4,-5,-5,-6,-6,-5,-5,-4 %N A359216 X-coordinates of a point moving in a counterclockwise undulating spiral in a square grid. %C A359216 Y-coordinates are given in A359217. %C A359216 The undulating spiral is %C A359216 y ^ %C A359216 | %C A359216 4 | 25--24 %C A359216 | | | %C A359216 3 | 27--26 23--22 %C A359216 | | | %C A359216 2 | 29--28 5---4 21--20 %C A359216 | | | | | %C A359216 1 | 31--30 7---6 3---2 19--18 %C A359216 | | | | | %C A359216 0 | 32--33 8---9 0---1 16--17 %C A359216 | | | | | %C A359216 -1 | 34--35 10--11 14--15 46--47 %C A359216 | | | | | %C A359216 -2 | 36--37 12--13 44--45 %C A359216 | | | %C A359216 -3 | 38--39 42--43 %C A359216 | | | %C A359216 -4 | 40--41 %C A359216 +------------------------------------> %C A359216 -4 -3 -2 -1 0 1 2 3 4 x %H A359216 Rémy Sigrist, <a href="/A359216/b359216.txt">Table of n, a(n) for n = 0..10081</a> %H A359216 Hans G. Oberlack, <a href="/A359217/a359217.pdf">Counterclockwise undulating spiral in a square grid</a> %H A359216 Rémy Sigrist, <a href="/A359216/a359216.gp.txt">PARI program</a> %H A359216 <a href="/index/Con#coordinates_2D_curves">Index entries for sequences related to coordinates of 2D curves</a> %F A359216 a(2*n) = A329116(n). - _Rémy Sigrist_, Apr 01 2023 %o A359216 (PARI) See Links section. %Y A359216 Cf. A329116, A359058, A359217. %K A359216 sign,walk %O A359216 0,8 %A A359216 _Hans G. Oberlack_, Dec 21 2022