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 A183051 #4 Mar 30 2012 18:57:12 %S A183051 0,3,3,3,3,2,2,2,2,2,2,2,2,3,1,1,3,1,1,3,1,1,3,1,1,2,2,4,2,2,2,4,2,2, %T A183051 2,4,2,2,2,4,2,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,4,4,2,2,2,4,4, %U A183051 4,2,2,2,4,4,4,2,2,2,4,4,4,2,2,2,4,5,3,3,3,3,3,3 %N A183051 Array of least knight's moves to points on the square |i|+|j|=n on infinite chessboard. %F A183051 See A065775. %e A183051 Top 5 rows: %e A183051 0 %e A183051 3 3 3 3 %e A183051 2 2 2 2 2 2 2 2 %e A183051 3 1 1 3 1 1 3 1 1 3 1 1 %e A183051 2 2 4 2 2 2 4 2 2 2 4 2 2 2 4 2 %e A183051 Row n has 4n numbers which form a square of points (i.e., unit squares) on an infinite chessboard. The first 3 of these concentric squares are represented as follows: %e A183051 ....2 %e A183051 ..2.3.2 %e A183051 2.3.0.3.2 %e A183051 ..2.3.2 %e A183051 ....2 %Y A183051 Cf. A065775, A183050, A183053. %K A183051 nonn,tabf %O A183051 1,2 %A A183051 _Clark Kimberling_, Dec 22 2010