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 A334475 #14 Mar 07 2021 10:14:41 %S A334475 0,0,1,1,0,0,1,2,2,3,3,2,3,3,2,1,0,0,1,1,0,0,1,2,2,3,4,4,5,5,4,4,5,6, %T A334475 6,7,7,6,7,7,6,5,4,5,4,4,5,6,7,7,6,6,7,7,6,5,5,4,3,2,3,3,2,1,0,0,1,1, %U A334475 0,0,1,2,2,3,3,2,3,3,2,1,0,0,1,1,0,0,1 %N A334475 a(n) is the X-coordinate of the n-th point of the space filling curve T defined in A334474; sequence A334476 gives Y-coordinates. %H A334475 Rémy Sigrist, <a href="/A334475/b334475.txt">Table of n, a(n) for n = 0..8255</a> %H A334475 Hugo Pfoertner, <a href="/plot2a?name1=A334475&name2=A334476&tform1=untransformed&tform2=untransformed&shift=0&radiop1=xy&drawlines=true">Illustration of curve T</a>, using Plot 2. %H A334475 Rémy Sigrist, <a href="/A334475/a334475.gp.txt">PARI program for A334475</a> %H A334475 <a href="/index/Con#coordinates_2D_curves">Index entries for sequences related to coordinates of 2D curves</a> %F A334475 A334474(A334476(n), a(n)) = n. %e A334475 The space filling curve T starts as follows: %e A334475 5| ... %e A334475 | | %e A334475 | | %e A334475 4| 16 %e A334475 | \ %e A334475 | \ %e A334475 3| 5 15-14-13 %e A334475 | |\ | %e A334475 | | \ | %e A334475 2| 4 6 11-12 %e A334475 | \ \ \ %e A334475 | \ \ \ %e A334475 1| 1 3 7 10 %e A334475 | |\ | | | %e A334475 | | \| | | %e A334475 0| 0 2 8--9 %e A334475 ---+------------- %e A334475 y/x| 0 1 2 3 %e A334475 - hence a(2) = a(3) = a(6) = a(15) = 1. %o A334475 (PARI) See Links section. %Y A334475 Cf. A334474, A334476. %K A334475 nonn %O A334475 0,8 %A A334475 _Rémy Sigrist_, May 02 2020