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 A196217 #7 Jun 02 2025 04:19:28 %S A196217 25,1629,21969,723029,21716929,608417005,17831030743,525537881675, %T A196217 15318916228421,446553011295591,13076767423341648,382744483425525635, %U A196217 11192520655926210678,327413888234566814665,9579556864719697800663 %N A196217 Number of nX7 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 3,0,1,2,4 for x=0,1,2,3,4. %C A196217 Every 0 is next to 0 3's, every 1 is next to 1 0's, every 2 is next to 2 1's, every 3 is next to 3 2's, every 4 is next to 4 4's %C A196217 Column 7 of A196218 %H A196217 R. H. Hardin, <a href="/A196217/b196217.txt">Table of n, a(n) for n = 1..45</a> %e A196217 Some solutions for n=4 %e A196217 ..0..1..2..1..0..0..0....0..2..1..0..1..2..1....0..0..1..1..1..0..1 %e A196217 ..0..1..2..2..1..1..1....0..1..2..0..1..2..0....0..0..2..0..2..1..2 %e A196217 ..2..1..1..0..1..1..1....0..2..3..1..1..1..1....1..2..1..0..2..1..2 %e A196217 ..1..0..1..1..2..0..0....0..1..2..1..0..0..1....1..0..1..1..1..0..1 %K A196217 nonn %O A196217 1,1 %A A196217 _R. H. Hardin_ Sep 29 2011