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 A196679 #8 Jun 02 2025 04:30:05 %S A196679 1,9,58,2245,188078,39696088,23029545105,36239510088523 %N A196679 Number of n X n 0..4 arrays with each element x equal to the number of its horizontal and vertical neighbors equal to 4,0,1,2,3 for x=0,1,2,3,4. %C A196679 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 A196679 Diagonal of A196685 %e A196679 Some solutions for n=4 %e A196679 ..1..0..0..0....1..1..1..2....0..1..2..1....0..0..2..1....0..2..1..2 %e A196679 ..1..2..0..0....0..0..0..1....1..2..0..0....0..2..1..0....1..1..0..1 %e A196679 ..0..1..2..0....0..0..0..1....1..2..0..0....2..1..2..0....2..1..0..1 %e A196679 ..0..1..1..0....1..1..1..2....0..1..2..1....1..0..0..0....0..2..1..2 %K A196679 nonn %O A196679 1,2 %A A196679 _R. H. Hardin_ Oct 05 2011