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 A302675 #4 Apr 11 2018 12:24:58 %S A302675 3,3,8,7,11,18,29,47,76,123,199,322,521,843,1364,2207,3571,5778,9349, %T A302675 15127,24476,39603,64079,103682,167761,271443,439204,710647,1149851, %U A302675 1860498,3010349,4870847,7881196,12752043,20633239,33385282,54018521 %N A302675 Number of nX3 0..1 arrays with every element equal to 0, 1, 4 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. %C A302675 Column 3 of A302680. %H A302675 R. H. Hardin, <a href="/A302675/b302675.txt">Table of n, a(n) for n = 1..210</a> %F A302675 Empirical: a(n) = a(n-1) +a(n-2) for n>5 %e A302675 Some solutions for n=5 %e A302675 ..0..1..0. .0..0..0. .0..1..0. .0..1..0. .0..0..0. .0..0..0. .0..1..0 %e A302675 ..0..0..0. .0..1..0. .0..1..0. .0..1..0. .0..1..0. .0..1..0. .0..0..0 %e A302675 ..0..1..0. .0..1..0. .0..0..0. .0..0..0. .0..1..0. .0..1..0. .1..1..1 %e A302675 ..0..1..0. .0..1..0. .0..1..0. .1..1..1. .0..1..0. .0..0..0. .1..0..1 %e A302675 ..0..1..0. .0..1..0. .0..1..0. .1..0..1. .0..0..0. .0..1..0. .1..0..1 %Y A302675 Cf. A302680. %K A302675 nonn %O A302675 1,1 %A A302675 _R. H. Hardin_, Apr 11 2018