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 A323469 #9 Apr 30 2021 21:23:23 %S A323469 -1,2016,3723,13103,14570,26967,101250,158735,132688,220439,144841, %T A323469 646728,350720,66183,75259,248764,118694,307483,238208,189159,139639, %U A323469 183821,151016,171076,114187,262235,178612,257632,124475,178862,143674,196795,60707,309820 %N A323469 On a spirally numbered square grid, with labels starting at 1, this is the number of steps that a (1,n) leaper makes before getting trapped, or -1 if it never gets trapped. %C A323469 A (1,2) leaper is a chess knight. %C A323469 a(2)-a(5) were computed by _Daniël Karssen_. %H A323469 Rémy Sigrist, <a href="/A323469/b323469.txt">Table of n, a(n) for n = 1..1000</a> %H A323469 N. J. A. Sloane and Brady Haran, <a href="https://www.youtube.com/watch?v=RGQe8waGJ4w">The Trapped Knight</a>, Numberphile video (2019) %Y A323469 The sequences involved in this set of related sequences are A316884, A316967, A316667, A316328, A317106, A317105, A317416, A317415, A317438, A317437, and A323469, A323470, A323471, A323472. %K A323469 sign %O A323469 1,2 %A A323469 _N. J. A. Sloane_, Jan 28 2019 %E A323469 More terms from _Rémy Sigrist_, Jan 29 2019