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 A303464 #4 Apr 24 2018 10:39:46 %S A303464 4,29,170,1033,6369,39098,240109,1476141,9071642,55751425,342663945, %T A303464 2106046874,12944002597,79556015733,488963529146,3005245731481, %U A303464 18470721790257,113523996378746,697736565265309,4288400399533821 %N A303464 Number of nX3 0..1 arrays with every element equal to 0, 1, 2, 3, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. %C A303464 Column 3 of A303469. %H A303464 R. H. Hardin, <a href="/A303464/b303464.txt">Table of n, a(n) for n = 1..210</a> %F A303464 Empirical: a(n) = 7*a(n-1) -5*a(n-2) +20*a(n-3) -144*a(n-4) +72*a(n-5) for n>6 %e A303464 Some solutions for n=5 %e A303464 ..0..1..0. .0..0..1. .0..0..1. .0..0..1. .0..1..1. .0..0..1. .0..1..0 %e A303464 ..1..1..1. .1..1..1. .1..0..1. .0..1..0. .0..0..1. .1..0..1. .1..1..0 %e A303464 ..0..0..0. .1..1..1. .1..0..0. .1..0..0. .1..0..1. .1..0..1. .0..0..0 %e A303464 ..1..0..0. .1..0..0. .0..1..0. .0..0..0. .0..0..0. .1..1..0. .1..0..1 %e A303464 ..1..1..1. .1..0..1. .0..1..1. .1..0..1. .0..1..1. .1..0..1. .1..0..0 %Y A303464 Cf. A303469. %K A303464 nonn %O A303464 1,1 %A A303464 _R. H. Hardin_, Apr 24 2018