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 A204976 #8 Jul 22 2025 18:29:07 %S A204976 82,40344,3074889,311275169,30057359681,2924321664147,284567725886961, %T A204976 27695578120521405,2695539138454039643,262351473887992967184, %U A204976 25534043844803329717305,2485171474074376861287947 %N A204976 Number of nX6 0..2 arrays with no occurrence of three equal elements in a row horizontally, vertically, diagonally or antidiagonally, and new values 0..2 introduced in row major order. %C A204976 Column 6 of A204978 %H A204976 R. H. Hardin, <a href="/A204976/b204976.txt">Table of n, a(n) for n = 1..53</a> %e A204976 Some solutions for n=5 %e A204976 ..0..1..2..1..0..2....0..0..1..0..1..0....0..0..1..2..2..0....0..1..0..2..1..2 %e A204976 ..2..0..0..2..1..0....0..0..2..1..0..0....0..0..2..1..2..0....2..0..2..2..1..0 %e A204976 ..1..2..1..2..0..2....1..1..2..1..2..2....1..1..2..2..0..1....2..1..1..0..2..1 %e A204976 ..2..2..0..1..2..0....2..0..0..2..0..0....1..2..1..2..1..2....0..1..0..2..0..0 %e A204976 ..2..1..0..0..2..0....1..1..0..2..1..0....0..1..2..0..1..2....2..2..0..2..0..2 %K A204976 nonn %O A204976 1,1 %A A204976 _R. H. Hardin_ Jan 21 2012