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 A231320 #7 Jul 23 2025 06:24:26 %S A231320 1536,192192,30645600,4509951264,677392128096,101255199764448, %T A231320 15154743446853216,2267704492520687136,339353240593608062304, %U A231320 50782606894918838006496,7599400278857398619862624 %N A231320 Number of (n+1)X(4+1) 0..2 arrays with no element equal to a strict majority of its diagonal and antidiagonal neighbors, with values 0..2 introduced in row major order. %C A231320 Column 4 of A231324 %H A231320 R. H. Hardin, <a href="/A231320/b231320.txt">Table of n, a(n) for n = 1..210</a> %H A231320 R. H. Hardin, <a href="/A231320/a231320.txt">Empirical recurrence of order 81</a> %F A231320 Empirical recurrence of order 81 (see link above) %e A231320 Some solutions for n=2 %e A231320 ..0..1..2..0..1....0..0..0..1..0....0..1..0..2..0....0..0..0..0..1 %e A231320 ..0..1..2..2..0....2..1..0..2..1....0..2..2..1..0....1..2..2..0..0 %e A231320 ..2..0..2..2..0....0..2..1..2..0....1..1..2..0..0....1..0..0..1..2 %K A231320 nonn %O A231320 1,1 %A A231320 _R. H. Hardin_, Nov 07 2013