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 A233225 #6 Jul 23 2025 07:56:42 %S A233225 6,174,8231,420948,21895530,1142726121,59679029456,3117164734533, %T A233225 162820623245643,8504746957840386,444236096357832461, %U A233225 23204188477204907670,1212045554583039193836,63309882191615788539747 %N A233225 Number of nX3 0..5 arrays with no element x(i,j) adjacent to value 5-x(i,j) horizontally, diagonally, antidiagonally or vertically, top left element zero, and 1 appearing before 2 3 and 4, and 2 appearing before 3 in row major order. %C A233225 Column 3 of A233230 %H A233225 R. H. Hardin, <a href="/A233225/b233225.txt">Table of n, a(n) for n = 1..210</a> %F A233225 Empirical: a(n) = 66*a(n-1) -748*a(n-2) +1422*a(n-3) +5006*a(n-4) -16598*a(n-5) +10288*a(n-6) +8658*a(n-7) -10189*a(n-8) +2228*a(n-9) -132*a(n-10) %e A233225 Some solutions for n=3 %e A233225 ..0..0..1....0..1..5....0..0..1....0..1..2....0..1..2....0..1..2....0..1..1 %e A233225 ..0..1..0....1..1..2....2..1..3....2..0..2....2..1..0....0..1..1....0..0..2 %e A233225 ..1..2..2....3..1..2....0..1..5....2..2..0....2..0..1....0..3..3....1..2..2 %K A233225 nonn %O A233225 1,1 %A A233225 _R. H. Hardin_, Dec 06 2013