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 A205311 #8 Apr 21 2021 13:23:08 %S A205311 8,84,2606,193664,33865634,13956665238,13574876544398, %T A205311 31191658416342676,169426507164530254382,2176592549084872196370726, %U A205311 66158464020552857153017287242,4759146677426447759184119036493678 %N A205311 Number of (n+1) X (n+1) 0..1 arrays with every 2 X 2 subblock having the same number of equal edges, and new values 0..1 introduced in row major order. %C A205311 Diagonal of A205318. %H A205311 R. H. Hardin, <a href="/A205311/b205311.txt">Table of n, a(n) for n = 1..14</a> %e A205311 Some solutions for n=4 %e A205311 ..0..1..1..1..0....0..1..0..0..0....0..1..1..0..0....0..0..0..0..1 %e A205311 ..1..1..0..1..0....1..1..0..1..0....0..1..0..0..1....0..1..0..1..1 %e A205311 ..1..0..0..0..0....0..0..0..0..0....1..1..1..0..0....0..1..1..1..0 %e A205311 ..0..0..1..0..1....1..1..0..1..0....0..0..1..0..1....0..1..0..1..1 %e A205311 ..0..1..1..0..0....1..0..0..1..0....0..1..1..0..1....1..1..1..1..0 %Y A205311 Cf. A205318. %K A205311 nonn %O A205311 1,1 %A A205311 _R. H. Hardin_ Jan 25 2012