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 A230169 #7 Jun 02 2025 08:41:26 %S A230169 0,27,3787,4722977,49754476927,4381081731832923,3274958849115023706081 %N A230169 Number of n X n 0..2 arrays x(i,j) with each element horizontally, vertically, diagonally or antidiagonally next to at least one element with value 2-x(i,j). %C A230169 Diagonal of A230176 %e A230169 Some solutions for n=3 %e A230169 ..1..0..0....0..2..1....0..0..1....1..0..2....1..1..0....0..0..2....2..1..1 %e A230169 ..1..2..0....1..2..1....2..0..1....1..0..2....1..0..2....2..1..2....2..0..1 %e A230169 ..2..0..2....1..0..0....1..1..2....1..1..0....1..2..2....0..1..1....0..2..1 %K A230169 nonn %O A230169 1,2 %A A230169 _R. H. Hardin_, Oct 11 2013