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 A222772 #6 Jul 23 2025 03:03:04 %S A222772 0,20,96,465,2608,15077,89811,544302,3349328,20823047,130535918, %T A222772 823585242,5221057054,33231082276,212180118775,1358528423728, %U A222772 8718262087314,56062919553225,361148981248207,2330144611056838 %N A222772 Number of 4Xn 0..1 arrays with exactly floor(4Xn/2) elements unequal to at least one horizontal or antidiagonal neighbor, with new values introduced in row major 0..1 order. %C A222772 Row 4 of A222769 %H A222772 R. H. Hardin, <a href="/A222772/b222772.txt">Table of n, a(n) for n = 1..45</a> %e A222772 Some solutions for n=3 %e A222772 ..0..0..0....0..0..0....0..0..0....0..0..0....0..0..1....0..0..1....0..0..0 %e A222772 ..0..1..0....1..1..1....0..0..1....0..0..0....0..1..0....0..0..0....0..0..1 %e A222772 ..1..0..0....0..1..1....0..0..0....0..1..0....0..0..0....0..1..1....0..0..1 %e A222772 ..0..0..0....1..1..1....0..1..1....0..1..1....0..0..0....1..1..1....0..1..1 %K A222772 nonn %O A222772 1,2 %A A222772 _R. H. Hardin_ Mar 05 2013