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 A304266 #4 May 09 2018 10:12:11 %S A304266 5,5,10,21,50,116,259,601,1397,3196,7359,17016,39172,90185,208017, %T A304266 479413,1104402,2545521,5866934,13519272,31155923,71803941,165473389, %U A304266 381338852,878829251,2025313404,4667430712,10756397233,24788787493,57127147381 %N A304266 Number of nX4 0..1 arrays with every element unequal to 0, 1, 5 or 8 king-move adjacent elements, with upper left element zero. %C A304266 Column 4 of A304270. %H A304266 R. H. Hardin, <a href="/A304266/b304266.txt">Table of n, a(n) for n = 1..210</a> %F A304266 Empirical: a(n) = a(n-1) +a(n-2) +5*a(n-3) +a(n-4) -3*a(n-5) -3*a(n-6) for n>7 %e A304266 Some solutions for n=5 %e A304266 ..0..0..0..0. .0..0..0..0. .0..0..1..0. .0..0..0..0. .0..0..1..0 %e A304266 ..0..0..0..0. .0..0..0..0. .0..0..0..0. .0..0..0..0. .0..0..0..0 %e A304266 ..0..0..0..0. .1..0..0..1. .0..0..0..0. .0..0..0..0. .0..0..0..0 %e A304266 ..0..0..0..0. .0..0..0..0. .0..0..0..0. .0..0..0..1. .0..0..0..0 %e A304266 ..0..1..0..0. .0..0..0..0. .0..0..1..0. .0..0..0..0. .0..0..0..0 %Y A304266 Cf. A304270. %K A304266 nonn %O A304266 1,1 %A A304266 _R. H. Hardin_, May 09 2018