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 A295776 #8 Feb 22 2019 10:04:54 %S A295776 5,19,56,198,665,2213,7479,25105,84326,283532,952661,3201517,10759441, %T A295776 36157455,121511416,408352614,1372308917,4611790689,15498404475, %U A295776 52083999509,175033735054,588219141252,1976771852673,6643148349849 %N A295776 Number of n X 3 0..1 arrays with each 1 adjacent to 0 or 2 king-move neighboring 1s. %H A295776 R. H. Hardin, <a href="/A295776/b295776.txt">Table of n, a(n) for n = 1..210</a> %F A295776 Empirical: a(n) = 2*a(n-1) + 3*a(n-2) + 6*a(n-3) - 3*a(n-4) + 2*a(n-5). %F A295776 Empirical g.f.: x*(5 + 9*x + 3*x^2 - x^3 + 2*x^4) / (1 - 2*x - 3*x^2 - 6*x^3 + 3*x^4 - 2*x^5). - _Colin Barker_, Feb 22 2019 %e A295776 Some solutions for n=7: %e A295776 ..1..1..0. .0..0..0. .1..0..0. .0..0..0. .0..0..1. .1..0..0. .0..0..0 %e A295776 ..0..1..0. .0..0..0. .0..0..0. .0..0..0. .0..0..0. .0..0..1. .0..0..0 %e A295776 ..0..0..0. .0..0..0. .0..0..1. .0..1..0. .0..1..1. .0..0..0. .0..0..0 %e A295776 ..0..1..1. .0..1..1. .1..0..0. .0..0..0. .0..0..1. .0..1..0. .1..0..0 %e A295776 ..0..1..0. .0..1..0. .0..0..1. .1..0..1. .1..0..0. .1..0..1. .0..0..0 %e A295776 ..0..0..0. .0..0..0. .1..0..0. .0..0..0. .1..1..0. .1..0..1. .0..1..0 %e A295776 ..1..0..1. .0..0..0. .0..0..0. .0..0..0. .0..0..0. .0..1..0. .0..1..1 %Y A295776 Column 3 of A295781. %K A295776 nonn %O A295776 1,1 %A A295776 _R. H. Hardin_, Nov 27 2017