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 A163334 #39 Feb 16 2025 08:33:11 %S A163334 0,1,5,2,4,6,15,3,7,47,16,14,8,46,48,17,13,9,45,49,53,18,12,10,44,50, %T A163334 52,54,19,23,11,43,39,51,55,59,20,22,24,42,40,38,56,58,60,141,21,25, %U A163334 29,41,37,69,57,61,425,142,140,26,28,30,36,70,68,62,424,426,143,139 %N A163334 Peano curve in an n X n grid, starting rightwards from the top left corner, listed antidiagonally as A(0,0), A(0,1), A(1,0), A(0,2), A(1,1), A(2,0), ... . %H A163334 Antti Karttunen, <a href="/A163334/b163334.txt">Table of n, a(n) for n = 0..13202</a> %H A163334 E. H. Moore, <a href="https://doi.org/10.1090/S0002-9947-1900-1500526-4">On Certain Crinkly Curves</a>, Transactions of the American Mathematical Society, volume 1, number 1, 1900, pages 72-90. (And <a href="https://doi.org/10.1090/S0002-9947-1900-1500428-3/">errata</a>.) See section 7 (and in figure 3 rotate -90 degrees for the table here). %H A163334 Giuseppe Peano, <a href="https://doi.org/10.1007/BF01199438">Sur une courbe, qui remplit toute une aire plane</a>, Mathematische Annalen, volume 36, number 1, 1890, pages 157-160. Also <a href="https://eudml.org/doc/157489">EUDML</a> (link to GDZ). %H A163334 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/HilbertCurve.html">Hilbert curve</a> (this curve called "Hilbert II"). %H A163334 Wikipedia, <a href="http://en.wikipedia.org/wiki/Self-avoiding_walk">Self-avoiding walk</a> %H A163334 Wikipedia, <a href="http://en.wikipedia.org/wiki/Space-filling_curve">Space-filling curve</a> %H A163334 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %F A163334 a(n) = A163332(A163328(n)). %e A163334 The top left 9 X 9 corner of the array shows how this surjective self-avoiding walk begins (connect the terms in numerical order, 0-1-2-3-...): %e A163334 0 1 2 15 16 17 18 19 20 %e A163334 5 4 3 14 13 12 23 22 21 %e A163334 6 7 8 9 10 11 24 25 26 %e A163334 47 46 45 44 43 42 29 28 27 %e A163334 48 49 50 39 40 41 30 31 32 %e A163334 53 52 51 38 37 36 35 34 33 %e A163334 54 55 56 69 70 71 72 73 74 %e A163334 59 58 57 68 67 66 77 76 75 %e A163334 60 61 62 63 64 65 78 79 80 %t A163334 b[{n_, k_}, {m_}] := (A[k, n] = m - 1); %t A163334 MapIndexed[b, List @@ PeanoCurve[4][[1]]]; %t A163334 Table[A[n - k, k], {n, 0, 12}, {k, n, 0, -1}] // Flatten (* _Jean-François Alcover_, Mar 07 2021 *) %Y A163334 Transpose: A163336. Inverse: A163335. One-based version: A163338. Row sums: A163342. Row 0: A163480. Column 0: A163481. Central diagonal: A163343. %Y A163334 See also: A163528-A163529, A163531, A163534, A163536, A163897. %Y A163334 See A163357 and A163359 for the Hilbert curve. %K A163334 nonn,tabl,look %O A163334 0,3 %A A163334 _Antti Karttunen_, Jul 29 2009 %E A163334 Links to further derived sequences added by _Antti Karttunen_, Sep 21 2009 %E A163334 Name corrected by _Kevin Ryde_, Aug 22 2020