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 A303417 #4 Apr 23 2018 10:52:04 %S A303417 8,128,1985,30897,480960,7486369,116529645,1813851698,28233652317, %T A303417 439473157219,6840654335738,106478748377005,1657403414891639, %U A303417 25798444493138200,401567736789419233,6250634501358061189 %N A303417 Number of nX4 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 A303417 Column 4 of A303421. %H A303417 R. H. Hardin, <a href="/A303417/b303417.txt">Table of n, a(n) for n = 1..210</a> %F A303417 Empirical: a(n) = 14*a(n-1) +21*a(n-2) +54*a(n-3) -23*a(n-4) -18*a(n-5) -20*a(n-6) %e A303417 Some solutions for n=5 %e A303417 ..0..0..0..0. .0..0..0..0. .0..0..0..0. .0..0..0..1. .0..0..0..0 %e A303417 ..1..0..1..1. .0..0..0..0. .0..1..1..0. .1..0..1..0. .1..1..1..0 %e A303417 ..0..0..0..1. .1..1..1..1. .1..1..1..1. .0..1..1..1. .0..1..0..1 %e A303417 ..0..1..1..1. .0..0..0..0. .0..0..1..0. .0..0..1..1. .1..0..0..0 %e A303417 ..1..1..1..0. .0..0..0..1. .0..1..0..1. .1..1..0..1. .0..0..0..1 %Y A303417 Cf. A303421. %K A303417 nonn %O A303417 1,1 %A A303417 _R. H. Hardin_, Apr 23 2018