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 A208288 #10 Jun 30 2018 14:24:20 %S A208288 8,64,216,984,3984,16872,70216,294192,1229400,5142728,21504256, %T A208288 89933368,376090120,1572797488,6577333928,27506063752,115028758000, %U A208288 481043815944,2011697870456,8412806681456,35181880551080,147128631386264 %N A208288 Number of 4 X n 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 0 1 and 1 1 0 vertically. %C A208288 Row 4 of A208287. %H A208288 R. H. Hardin, <a href="/A208288/b208288.txt">Table of n, a(n) for n = 1..210</a> %F A208288 Empirical: a(n) = 3*a(n-1) + 6*a(n-2) - 4*a(n-3) - 2*a(n-4) + a(n-5). %F A208288 Empirical g.f.: 8*x*(1 + 5*x - 3*x^2 - 2*x^3 + x^4) / ((1 + x - x^2)*(1 - 4*x - x^2 + x^3)). - _Colin Barker_, Jun 30 2018 %e A208288 Some solutions for n=4: %e A208288 ..0..1..1..0....1..1..0..0....1..0..1..0....0..1..1..0....1..0..1..1 %e A208288 ..1..1..0..0....1..0..1..0....0..1..0..0....0..1..1..0....0..1..1..0 %e A208288 ..1..1..0..0....1..1..0..0....1..1..1..0....0..1..1..0....1..0..1..1 %e A208288 ..1..1..0..0....1..1..1..0....0..1..1..0....0..1..1..0....0..1..1..1 %Y A208288 Cf. A208287. %K A208288 nonn %O A208288 1,1 %A A208288 _R. H. Hardin_, Feb 25 2012