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 A196211 #8 Jun 02 2025 04:18:59 %S A196211 1,9,58,2161,173216,33962624,17831030743,24799094512239 %N A196211 Number of n X n 0..4 arrays with each element x equal to the number of its horizontal and vertical neighbors equal to 3,0,1,2,4 for x=0,1,2,3,4. %C A196211 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 A196211 Diagonal of A196218 %e A196211 Some solutions for n=4 %e A196211 ..1..1..0..0....1..2..0..1....1..0..1..1....0..0..1..1....0..1..2..1 %e A196211 ..0..1..1..1....0..1..1..1....1..0..2..0....1..1..1..0....0..1..2..0 %e A196211 ..1..1..1..1....0..2..1..0....2..1..1..0....2..1..1..0....0..1..1..2 %e A196211 ..1..0..0..0....0..0..1..1....0..2..1..0....0..0..1..1....1..1..0..1 %K A196211 nonn %O A196211 1,2 %A A196211 _R. H. Hardin_ Sep 29 2011