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 A196331 #8 Jun 02 2025 04:22:33 %S A196331 1,5,7,335,3793,237905,20775275,5845172493,2321484416437 %N A196331 Number of n X n 0..4 arrays with each element x equal to the number of its horizontal and vertical neighbors equal to 4,0,3,1,2 for x=0,1,2,3,4. %C A196331 Every 0 is next to 0 4's, every 1 is next to 1 0's, every 2 is next to 2 3's, every 3 is next to 3 1's, every 4 is next to 4 2's %C A196331 Diagonal of A196337 %e A196331 Some solutions for n=4 %e A196331 ..0..1..1..0....1..1..0..1....1..0..0..1....0..0..0..0....0..1..1..0 %e A196331 ..0..3..1..0....0..3..1..3....1..0..0..1....1..1..3..1....0..1..3..0 %e A196331 ..0..1..1..0....0..1..1..1....1..1..1..1....1..1..1..3....0..1..1..0 %e A196331 ..1..3..1..0....1..1..0..0....0..1..1..0....0..0..0..1....1..3..1..0 %K A196331 nonn %O A196331 1,2 %A A196331 _R. H. Hardin_ Oct 01 2011