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 A303423 #4 Apr 23 2018 10:56:33 %S A303423 8,128,1988,30897,480953,7486281,116517744,1813509273,28226012078, %T A303423 439318146284,6837678112091,106423655020443,1656409429611799, %U A303423 25780849141739720,401260805513420875,6245342547417157374 %N A303423 Number of 4Xn 0..1 arrays with every element equal to 0, 1, 2, 3, 4 or 5 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. %C A303423 Row 4 of A303421. %H A303423 R. H. Hardin, <a href="/A303423/b303423.txt">Table of n, a(n) for n = 1..210</a> %F A303423 Empirical: a(n) = 14*a(n-1) +12*a(n-2) +175*a(n-3) +283*a(n-4) -235*a(n-5) -144*a(n-6) +67*a(n-7) -135*a(n-8) +50*a(n-9) %e A303423 Some solutions for n=5 %e A303423 ..0..0..0..0..1. .0..0..0..1..0. .0..1..0..1..1. .0..0..0..1..1 %e A303423 ..0..0..0..0..0. .0..1..1..0..0. .0..0..1..1..1. .0..0..0..0..1 %e A303423 ..0..1..1..0..1. .0..1..0..0..1. .0..1..1..1..0. .0..0..1..1..1 %e A303423 ..0..0..1..1..1. .0..0..0..1..1. .1..0..1..1..1. .0..0..0..1..0 %Y A303423 Cf. A303421. %K A303423 nonn %O A303423 1,1 %A A303423 _R. H. Hardin_, Apr 23 2018