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 A303097 #6 Jun 21 2022 23:43:50 %S A303097 1,15,77,486,2869,17229,102952,616065,3685099,22045482,131879323, %T A303097 788928513,4719516650,28233043741,168895389127,1010364108842, %U A303097 6044188782411,36157478162593,216300858973502,1293952564919109 %N A303097 Number of n X 3 0..1 arrays with every element equal to 1, 2, 3, 4 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. %C A303097 Column 3 of A303102. %H A303097 R. H. Hardin, <a href="/A303097/b303097.txt">Table of n, a(n) for n = 1..210</a> %F A303097 Empirical: a(n) = 5*a(n-1) +9*a(n-2) -14*a(n-3) -28*a(n-4) -6*a(n-5) +32*a(n-6) +10*a(n-7) -2*a(n-8) +32*a(n-9) -32*a(n-11). %e A303097 Some solutions for n=5 %e A303097 ..0..0..0. .0..0..0. .0..0..0. .0..0..0. .0..0..0. .0..1..0. .0..1..1 %e A303097 ..1..1..0. .1..1..0. .0..0..1. .0..1..1. .1..1..1. .0..0..1. .1..0..1 %e A303097 ..1..1..0. .0..1..1. .1..1..0. .0..1..1. .1..0..0. .0..1..1. .0..1..0 %e A303097 ..1..0..1. .0..0..1. .0..0..1. .0..0..1. .0..0..1. .1..1..0. .0..0..1 %e A303097 ..0..0..0. .1..1..1. .1..1..1. .1..1..1. .1..1..0. .0..0..1. .0..1..1 %Y A303097 Cf. A303102. %K A303097 nonn %O A303097 1,2 %A A303097 _R. H. Hardin_, Apr 18 2018