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 A231400 #6 Jul 23 2025 06:27:52 %S A231400 12,20,272,1096,8340,55788,345022,2502891,16525492,113585134, %T A231400 799820476,5455236715,38507382540,268963425191,1882384615623, %U A231400 13300278749856,93433472155344,659971112697126,4663864398488500,32941704521261841 %N A231400 Number of (4+1)X(n+1) 0..2 arrays with no element unequal to a strict majority of its horizontal, diagonal and antidiagonal neighbors, with values 0..2 introduced in row major order. %C A231400 Row 4 of A231396 %H A231400 R. H. Hardin, <a href="/A231400/b231400.txt">Table of n, a(n) for n = 1..210</a> %e A231400 Some solutions for n=5 %e A231400 ..0..0..0..0..0..1....0..0..0..1..1..1....0..0..1..0..1..1....0..0..0..0..0..0 %e A231400 ..1..1..0..0..1..1....1..1..1..0..1..1....1..1..0..1..0..0....0..0..0..0..1..1 %e A231400 ..1..1..1..1..1..1....1..1..0..0..0..0....1..1..1..0..0..0....1..1..1..1..1..1 %e A231400 ..0..0..1..1..1..1....1..0..1..0..0..0....0..0..0..1..0..0....1..1..2..2..1..1 %e A231400 ..0..0..0..0..0..0....0..1..0..1..1..1....0..0..1..1..1..0....1..2..2..2..2..2 %K A231400 nonn %O A231400 1,1 %A A231400 _R. H. Hardin_, Nov 08 2013