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 A197473 #7 Jun 02 2025 04:56:51 %S A197473 4,50,374,2824,22672,165200,1265828,9507212,72145488,544829612, %T A197473 4121917612,31166838320,235726500646,1782712177744,13482608699280, %U A197473 101968288116918,771180418816752,5832406885650952,44110365514811080 %N A197473 Number of nX6 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 0,1,0,0,0 for x=0,1,2,3,4. %C A197473 Every 0 is next to 0 0's, every 1 is next to 1 1's, every 2 is next to 2 0's, every 3 is next to 3 0's, every 4 is next to 4 0's %C A197473 Column 6 of A197475 %H A197473 R. H. Hardin, <a href="/A197473/b197473.txt">Table of n, a(n) for n = 1..210</a> %e A197473 Some solutions containing all values 0 to 4 for n=4 %e A197473 ..2..0..3..0..1..1....0..3..0..1..1..0....0..3..0..2..1..1....1..0..3..0..1..1 %e A197473 ..0..3..0..4..0..2....3..0..4..0..2..1....3..0..4..0..3..0....1..3..0..4..0..2 %e A197473 ..2..1..1..0..3..0....0..4..0..3..0..1....0..4..0..4..0..2....2..0..1..0..4..0 %e A197473 ..0..2..0..2..1..1....2..0..1..1..2..0....2..0..3..0..1..1....0..2..1..2..0..2 %K A197473 nonn %O A197473 1,1 %A A197473 _R. H. Hardin_ Oct 15 2011