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 A197198 #7 Jun 02 2025 04:46:13 %S A197198 13,178,1801,21803,247053,2873141,33176391,383262156,4432780869, %T A197198 51234398070,592247668688,6846309893866,79142347014020, %U A197198 914861421385891,10575600998801299,122251698517890245,1413202926345456663 %N A197198 Number of nX7 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 4,1,3,2,0 for x=0,1,2,3,4. %C A197198 Every 0 is next to 0 4's, every 1 is next to 1 1's, every 2 is next to 2 3's, every 3 is next to 3 2's, every 4 is next to 4 0's %C A197198 Column 7 of A197199 %H A197198 R. H. Hardin, <a href="/A197198/b197198.txt">Table of n, a(n) for n = 1..107</a> %e A197198 Some solutions for n=4 %e A197198 ..1..1..0..0..0..1..1....0..0..0..0..0..1..1....0..0..0..0..1..1..0 %e A197198 ..0..0..1..0..1..0..0....0..0..1..0..1..0..0....0..0..0..0..0..0..0 %e A197198 ..0..0..1..0..1..0..0....0..0..1..0..1..0..0....1..1..0..0..0..0..1 %e A197198 ..0..0..0..0..0..1..1....0..0..0..0..0..1..1....0..0..1..1..0..0..1 %K A197198 nonn %O A197198 1,1 %A A197198 _R. H. Hardin_ Oct 11 2011