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 A205588 #7 Jul 22 2025 18:56:46 %S A205588 69338,1910922,68604790,2444556894,88339585116,3232900348158, %T A205588 118372688297292,4345040364362660,159636203824214264, %U A205588 5867029054299935636,215694158623613862786,7930473571089262834558,291601723075905716037696 %N A205588 Number of (n+1)X7 0..2 arrays with no 2X2 subblock having the same number of equal edges as its horizontal or vertical neighbors, and new values 0..2 introduced in row major order. %C A205588 Column 6 of A205590 %H A205588 R. H. Hardin, <a href="/A205588/b205588.txt">Table of n, a(n) for n = 1..32</a> %e A205588 Some solutions for n=4 %e A205588 ..0..0..0..0..1..0..1....0..1..0..2..1..2..2....0..0..1..0..2..1..1 %e A205588 ..2..0..0..1..0..0..2....1..1..2..1..1..0..0....0..2..1..0..1..0..2 %e A205588 ..1..0..1..0..0..0..0....2..0..1..1..1..0..0....0..1..2..0..1..2..1 %e A205588 ..0..2..1..0..0..2..1....1..2..1..1..2..2..0....2..0..2..2..1..2..0 %e A205588 ..0..1..1..2..0..1..2....0..2..2..0..1..2..1....1..0..2..2..2..0..0 %K A205588 nonn %O A205588 1,1 %A A205588 _R. H. Hardin_ Jan 29 2012