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 A302516 #6 Jan 16 2022 01:12:11 %S A302516 4,4,11,15,21,52,118,220,408,852,1764,3460,6796,13732,27708,55140, %T A302516 109788,220132,441244,881380,1760796,3523812,7051548,14098660, %U A302516 28189468,56387812,112791324,225564900,451098396,902232292,1804527388,3608983780 %N A302516 Number of 3 X n 0..1 arrays with every element equal to 0, 1, 4 or 5 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. %C A302516 Row 3 of A302515. %H A302516 R. H. Hardin, <a href="/A302516/b302516.txt">Table of n, a(n) for n = 1..210</a> %F A302516 Empirical: a(n) = a(n-1) +2*a(n-3) +4*a(n-4) for n>7. %e A302516 Some solutions for n=5 %e A302516 ..0..1..0..1..1. .0..1..0..1..0. .0..1..0..1..1. .0..1..0..1..0 %e A302516 ..0..1..0..0..0. .0..0..0..1..0. .0..1..0..0..0. .0..1..0..1..0 %e A302516 ..0..1..0..1..0. .1..1..0..1..0. .0..1..0..1..1. .0..1..0..1..0 %Y A302516 Cf. A302515. %K A302516 nonn %O A302516 1,1 %A A302516 _R. H. Hardin_, Apr 09 2018