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 A197310 #8 Jun 02 2025 04:50:14 %S A197310 1,0,5,160,1033,24704,2241018,282284587,82874179361 %N A197310 Number of n X n 0..4 arrays with each element x equal to the number of its horizontal and vertical neighbors equal to 0,1,1,0,0 for x=0,1,2,3,4. %C A197310 Every 0 is next to 0 0's, every 1 is next to 1 1's, every 2 is next to 2 1's, every 3 is next to 3 0's, every 4 is next to 4 0's %C A197310 Diagonal of A197317 %e A197310 Some solutions for n=4 %e A197310 ..0..1..1..0....0..1..1..0....0..1..1..2....2..1..1..2....2..1..1..2 %e A197310 ..1..2..2..1....1..2..0..1....1..2..0..1....1..2..2..1....1..2..2..1 %e A197310 ..1..2..2..1....1..0..2..1....1..2..2..1....1..0..2..1....1..2..0..1 %e A197310 ..2..1..1..2....2..1..1..0....0..1..1..2....2..1..1..2....0..1..1..2 %K A197310 nonn %O A197310 1,3 %A A197310 _R. H. Hardin_ Oct 13 2011