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 A196684 #7 Jun 02 2025 04:30:26 %S A196684 25,1629,22461,796557,25142624,741925729,23029545105,718199634805, %T A196684 22138818455076,682005890331480,21125269566890884,654095412346594187, %U A196684 20229325302713363751,625878086264793074895,19368465617464223064077 %N A196684 Number of nX7 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 4,0,1,2,3 for x=0,1,2,3,4. %C A196684 Every 0 is next to 0 4'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 3's %C A196684 Column 7 of A196685 %H A196684 R. H. Hardin, <a href="/A196684/b196684.txt">Table of n, a(n) for n = 1..32</a> %e A196684 Some solutions for n=4 %e A196684 ..0..0..2..1..1..2..0....0..1..1..0..1..2..0....0..1..1..0..0..1..1 %e A196684 ..0..2..1..0..0..1..2....0..1..2..0..1..1..0....0..2..1..2..0..2..0 %e A196684 ..0..1..2..2..1..1..1....0..2..0..0..1..1..1....0..0..0..1..1..1..2 %e A196684 ..1..2..0..1..1..0..0....0..1..2..1..1..0..1....0..0..0..1..1..0..1 %K A196684 nonn %O A196684 1,1 %A A196684 _R. H. Hardin_ Oct 05 2011