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 A316668 #7 Aug 18 2019 04:34:00 %S A316668 1,2,3,5,4,7,8,9,6,10,14,13,12,11,16,17,18,19,20,15,21,27,26,25,24,23, %T A316668 22,29,30,31,32,33,34,35,28,36,44,43,42,41,40,39,38,37,46,47,48,49,50, %U A316668 51,52,53,54,45,55,65,64,63,62,61,60,59,58,57,56,67,68 %N A316668 Squares visited by king moves on a diagonally numbered board and moving to the lowest available unvisited square at each step. %C A316668 Board is numbered as follows: %C A316668 1 2 4 7 11 16 . %C A316668 3 5 8 12 17 . %C A316668 6 9 13 18 . %C A316668 10 14 19 . %C A316668 15 20 . %C A316668 21 . %C A316668 . %C A316668 Same as A316588 but with king move instead of knight move. %H A316668 Daniël Karssen, <a href="/A316668/b316668.txt">Table of n, a(n) for n = 1..100000</a> %H A316668 Daniël Karssen, <a href="/A316668/a316668.svg">Figure showing the first 26 steps of the sequence</a> %Y A316668 Cf. A316588, A316669, A316670, A316671. %K A316668 nonn %O A316668 1,2 %A A316668 _Daniël Karssen_, Jul 15 2018