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 A302966 #4 Apr 16 2018 11:56:10 %S A302966 4,32,154,786,3924,19868,100161,505908,2554201,12898093,65130456, %T A302966 328890172,1660800969,8386586118,42349950959,213855666444, %U A302966 1079912639341,5453263882696,27537493309346,139056822182155,702198983497508 %N A302966 Number of 3Xn 0..1 arrays with every element equal to 0, 1, 2, 3 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. %C A302966 Row 3 of A302965. %H A302966 R. H. Hardin, <a href="/A302966/b302966.txt">Table of n, a(n) for n = 1..210</a> %F A302966 Empirical: a(n) = 3*a(n-1) +15*a(n-2) -11*a(n-3) -64*a(n-4) -10*a(n-5) +73*a(n-6) +15*a(n-7) -7*a(n-8) +4*a(n-9) -30*a(n-10) -9*a(n-11) +8*a(n-12) for n>13 %e A302966 Some solutions for n=5 %e A302966 ..0..1..0..0..1. .0..1..0..1..1. .0..0..0..0..0. .0..1..0..1..1 %e A302966 ..1..1..1..0..1. .1..0..1..0..1. .1..0..1..1..0. .1..0..1..0..1 %e A302966 ..0..0..1..1..0. .1..0..1..0..1. .1..1..0..0..0. .0..0..1..1..0 %Y A302966 Cf. A302965. %K A302966 nonn %O A302966 1,1 %A A302966 _R. H. Hardin_, Apr 16 2018