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 A338290 #10 Oct 20 2020 19:28:38 %S A338290 1,10,12,3,9,6,4,15,7,2,18,5,35,8,14,11,29,24,32,27,55,48,28,23,13,20, %T A338290 34,39,17,16,40,19,21,22,46,41,25,44,50,71,79,74,26,45,47,42,76,69,43, %U A338290 38,70,63,105,66,148,99,65,36,98,61,37,94,62,31,33,54,30,85,53,124,84,51 %N A338290 Squares visited by either knight when a white knight and a black knight are moving on a spirally numbered board, always to the lowest available unvisited square; white moves first. %C A338290 Board is numbered with the square spiral: %C A338290 17--16--15--14--13 . %C A338290 | | . %C A338290 18 5---4---3 12 . %C A338290 | | | | . %C A338290 19 6 1---2 11 . %C A338290 | | | . %C A338290 20 7---8---9--10 . %C A338290 | . %C A338290 21--22--23--24--25--26 %C A338290 Both knights start on square 1, white moves to the lowest unvisited square (10), black then moves to the lowest unvisited square (12) and so on... %C A338290 This sequence is finite, on the 3758th move or the black knight's 1879th step, square 4242 is visited, after which white wins and the game is over. %C A338290 The sequences generated by 4 knights and 8 knights also produce new sequences not yet in the OEIS. %H A338290 N. J. A. Sloane and Brady Haran, <a href="https://www.youtube.com/watch?v=RGQe8waGJ4w">The Trapped Knight</a>, Numberphile video (2019). %Y A338290 Cf. A338288, A338289. %K A338290 nonn %O A338290 1,2 %A A338290 _Andrew Smith_, Oct 20 2020