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 A303237 #4 Apr 20 2018 10:52:00 %S A303237 1,11,18,55,181,494,1465,4415,12934,38423,114145,337914,1003161, %T A303237 2976083,8824906,26185191,77678573,230413110,683562697,2027805127, %U A303237 6015399582,17845009895,52937661977,157040038306,465863595657,1381994981979 %N A303237 Number of nX3 0..1 arrays with every element equal to 0, 2, 3, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. %C A303237 Column 3 of A303242. %H A303237 R. H. Hardin, <a href="/A303237/b303237.txt">Table of n, a(n) for n = 1..210</a> %F A303237 Empirical: a(n) = 4*a(n-1) -5*a(n-2) +16*a(n-3) -36*a(n-4) +32*a(n-5) -63*a(n-6) +64*a(n-7) -51*a(n-8) +4*a(n-9) +60*a(n-10) +16*a(n-11) +112*a(n-12) +64*a(n-13) %e A303237 Some solutions for n=5 %e A303237 ..0..0..1. .0..1..1. .0..1..0. .0..0..1. .0..0..0. .0..1..1. .0..1..1 %e A303237 ..0..0..1. .1..1..0. .0..1..0. .0..0..1. .1..0..0. .0..1..1. .1..1..0 %e A303237 ..1..0..0. .0..1..0. .0..1..0. .1..0..1. .1..0..1. .1..1..0. .0..1..1 %e A303237 ..0..0..1. .1..1..1. .1..1..1. .0..0..0. .1..0..0. .0..1..1. .0..1..1 %e A303237 ..0..0..1. .0..1..1. .0..1..1. .1..0..1. .1..0..0. .1..1..0. .0..1..1 %Y A303237 Cf. A303242. %K A303237 nonn %O A303237 1,2 %A A303237 _R. H. Hardin_, Apr 20 2018