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 A230752 #6 Jun 22 2022 10:51:02 %S A230752 2700,178608,13305708,820317888,51048476748,3154520054700, %T A230752 194576103540300,11996844809605932,739805051154249408, %U A230752 45610762080137185200,2812209212644935163212,173386992056092099438572 %N A230752 Number of (n+3) X (3+3) 0..2 arrays x(i,j) with each element diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 3, and upper left element zero. %C A230752 Column 3 of A230757. %H A230752 R. H. Hardin, <a href="/A230752/b230752.txt">Table of n, a(n) for n = 1..210</a> %e A230752 Some solutions for n=1 %e A230752 ..0..2..0..1..1..1....0..0..0..0..1..1....0..2..0..2..2..0....0..2..0..2..2..2 %e A230752 ..1..1..0..0..2..2....1..1..1..2..2..0....0..1..0..2..1..0....1..1..0..2..0..0 %e A230752 ..0..0..2..2..0..0....2..2..1..1..2..2....2..1..1..0..1..0....0..0..2..1..1..2 %e A230752 ..2..1..2..1..1..2....1..0..0..1..0..1....0..0..2..0..2..0....2..1..2..0..0..0 %Y A230752 Cf. A230757. %K A230752 nonn %O A230752 1,1 %A A230752 _R. H. Hardin_, Oct 29 2013