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 A302630 #4 Apr 10 2018 19:28:51 %S A302630 3,9,8,19,42,82,189,469,1029,2372,5661,12788,29440,69193,158299, %T A302630 364581,849888,1955567,4508226,10463966,24138613,55695301,128985441, %U A302630 297870624,687700145,1590857932,3675434388,8488858425,19626303139,45350971169 %N A302630 Number of nX3 0..1 arrays with every element equal to 0, 1, 3 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. %C A302630 Column 3 of A302635. %H A302630 R. H. Hardin, <a href="/A302630/b302630.txt">Table of n, a(n) for n = 1..210</a> %F A302630 Empirical: a(n) = a(n-1) +9*a(n-3) -4*a(n-4) +2*a(n-5) -10*a(n-6) +4*a(n-7) +4*a(n-9) for n>13 %e A302630 Some solutions for n=5 %e A302630 ..0..1..0. .0..1..0. .0..1..0. .0..1..0. .0..1..0. .0..1..0. .0..0..1 %e A302630 ..0..1..1. .0..1..0. .0..1..0. .0..0..0. .0..1..0. .0..1..1. .0..1..0 %e A302630 ..0..1..0. .0..1..0. .0..1..0. .0..1..0. .0..1..0. .0..1..0. .1..1..1 %e A302630 ..0..1..0. .0..1..0. .0..1..0. .0..1..0. .0..1..1. .0..1..0. .1..1..0 %e A302630 ..1..0..0. .0..0..1. .0..1..0. .1..0..0. .0..1..0. .0..0..1. .0..1..0 %Y A302630 Cf. A302635. %K A302630 nonn %O A302630 1,1 %A A302630 _R. H. Hardin_, Apr 10 2018