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 A283568 #4 Mar 11 2017 08:13:52 %S A283568 2,72,674,6812,60802,528436,4441052,36589848,296555892,2373574616, %T A283568 18804085974,147722885964,1152326125736,8934988081564,68923216977218, %U A283568 529275667161388,4048382091614590,30857555674174468,234469910144650842 %N A283568 Number of nX4 0..1 arrays with no 1 equal to more than one of its horizontal, diagonal and antidiagonal neighbors, with the exception of exactly one element. %C A283568 Column 4 of A283572. %H A283568 R. H. Hardin, <a href="/A283568/b283568.txt">Table of n, a(n) for n = 1..210</a> %F A283568 Empirical: a(n) = 12*a(n-1) -16*a(n-2) -148*a(n-3) +122*a(n-4) +8*a(n-5) -1218*a(n-6) +1236*a(n-7) +1851*a(n-8) -3776*a(n-9) +3314*a(n-10) +5408*a(n-11) -7569*a(n-12) -2532*a(n-13) +2620*a(n-14) +320*a(n-15) -256*a(n-16) %e A283568 Some solutions for n=4 %e A283568 ..0..1..0..0. .1..0..0..1. .1..0..0..0. .0..0..0..1. .1..0..0..1 %e A283568 ..0..0..0..1. .0..0..0..0. .0..0..1..0. .1..0..0..1. .0..0..0..0 %e A283568 ..0..1..0..1. .1..1..0..0. .1..1..0..0. .1..1..0..1. .0..0..1..1 %e A283568 ..0..0..1..0. .0..1..0..0. .1..0..0..1. .0..0..0..0. .1..0..1..0 %Y A283568 Cf. A283572. %K A283568 nonn %O A283568 1,1 %A A283568 _R. H. Hardin_, Mar 11 2017