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 A222449 #7 Jan 16 2022 01:13:43 %S A222449 1,0,2,101,1847,161779,17977932,8774928190,4427986390487, %T A222449 10016765131595843 %N A222449 Number of n X n 0..1 arrays with exactly floor(n X n/2) elements unequal to at least one horizontal, vertical or antidiagonal neighbor, with new values introduced in row major 0..1 order. %C A222449 Diagonal of A222456. %e A222449 Some solutions for n=4 %e A222449 ..0..0..1..1....0..0..0..0....0..0..0..0....0..0..0..0....0..1..1..1 %e A222449 ..0..0..1..0....0..0..0..0....0..0..0..1....0..0..0..1....0..1..1..1 %e A222449 ..0..0..0..0....1..1..0..0....0..0..0..0....1..1..1..1....1..1..1..1 %e A222449 ..0..0..0..0....1..1..0..0....0..0..1..0....1..1..1..1....0..1..1..1 %Y A222449 Cf. A222456. %K A222449 nonn %O A222449 1,3 %A A222449 _R. H. Hardin_, Feb 20 2013