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 A318340 #4 Aug 24 2018 11:02:57 %S A318340 16,42,76,148,393,1115,3321,10111,30943,95244,293401,904986,2792217, %T A318340 8617223,26597072,82096253,253412398,782236683,2414640760,7453642765, %U A318340 23008358869,71023687464,219240636280,676766784339,2089089700480 %N A318340 Number of nX5 0..1 arrays with every element unequal to 0, 1, 2 or 6 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero. %C A318340 Column 5 of A318343. %H A318340 R. H. Hardin, <a href="/A318340/b318340.txt">Table of n, a(n) for n = 1..210</a> %F A318340 Empirical: a(n) = 3*a(n-1) +5*a(n-2) -12*a(n-3) -17*a(n-4) +20*a(n-5) +31*a(n-6) -13*a(n-7) -33*a(n-8) +a(n-9) +20*a(n-10) +2*a(n-11) -4*a(n-12) -3*a(n-13) +a(n-15) for n>18 %e A318340 Some solutions for n=5 %e A318340 ..0..1..1..1..1. .0..0..0..0..0. .0..1..1..0..0. .0..0..1..1..1 %e A318340 ..1..0..1..1..1. .0..1..0..0..1. .1..1..1..0..0. .0..1..1..1..1 %e A318340 ..1..1..1..1..1. .0..0..0..1..1. .1..1..1..0..0. .1..1..1..1..1 %e A318340 ..1..0..1..0..1. .0..0..1..1..0. .1..1..1..0..0. .1..0..1..1..1 %e A318340 ..1..1..1..1..0. .0..1..1..0..0. .1..1..1..0..0. .1..1..1..1..0 %Y A318340 Cf. A318343. %K A318340 nonn %O A318340 1,1 %A A318340 _R. H. Hardin_, Aug 24 2018