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 A302510 #6 Apr 07 2020 12:36:51 %S A302510 3,3,11,9,14,21,28,37,51,72,100,137,188,260,360,497,685,945,1305,1802, %T A302510 2487,3432,4737,6539,9026,12458,17195,23734,32760,45218,62413,86147, %U A302510 118907,164125,226538,312685,431592,595717,822255,1134940,1566532 %N A302510 Number of n X 3 0..1 arrays with every element equal to 0, 1, 4 or 5 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. %H A302510 R. H. Hardin, <a href="/A302510/b302510.txt">Table of n, a(n) for n = 1..210</a> %F A302510 Empirical: a(n) = a(n-1) +a(n-4) for n>7. %e A302510 Some solutions for n=5 %e A302510 ..0..1..0. .0..1..0. .0..1..0. .0..1..0. .0..0..0. .0..0..1. .0..0..1 %e A302510 ..0..1..0. .0..1..0. .0..1..0. .0..1..0. .0..1..0. .1..1..1. .1..1..1 %e A302510 ..0..1..0. .0..0..0. .0..1..0. .0..1..0. .0..1..0. .1..0..1. .1..0..1 %e A302510 ..0..1..0. .1..1..1. .0..0..0. .0..0..0. .0..0..0. .1..0..1. .1..0..1 %e A302510 ..0..1..0. .1..0..1. .0..1..1. .1..1..0. .1..1..0. .1..0..1. .1..1..1 %Y A302510 Column 3 of A302515. %K A302510 nonn %O A302510 1,1 %A A302510 _R. H. Hardin_, Apr 09 2018