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 A303713 #11 Apr 20 2020 00:07:29 %S A303713 1,1,5,17,81,343,1592,7551,34546,158402,734321,3389249,15610239, %T A303713 72045856,332515175,1533661362,7075164898,32644176977,150600651761, %U A303713 694773927239,3205360278072,14787893322847,68223139662242,314745564736962 %N A303713 Number of n X n 0..1 arrays with every element unequal to 0, 1 or 5 king-move adjacent elements, with upper left element zero. %C A303713 Diagonal of A303719. %H A303713 R. H. Hardin, <a href="/A303713/b303713.txt">Table of n, a(n) for n = 1..70</a> %F A303713 Empirical: a(n) = 3*a(n-1) +2*a(n-2) +28*a(n-3) -2*a(n-4) -42*a(n-5) -56*a(n-6) +50*a(n-7) -44*a(n-8) +30*a(n-9) -44*a(n-10) +2*a(n-11) +2*a(n-12) -a(n-14) +a(n-15) for n>18. %e A303713 Some solutions for n=5 %e A303713 ..0..0..0..0..0. .0..0..0..1..0. .0..0..0..1..0. .0..0..0..0..0 %e A303713 ..0..0..0..0..0. .0..0..0..0..0. .0..0..0..0..0. .0..0..0..0..0 %e A303713 ..0..0..0..0..0. .0..0..0..0..0. .0..0..0..0..0. .0..0..0..0..1 %e A303713 ..1..0..0..0..0. .1..0..0..0..0. .0..0..0..0..0. .0..0..0..0..0 %e A303713 ..0..0..0..1..0. .0..0..0..0..0. .0..0..1..0..0. .0..0..0..0..0 %Y A303713 Cf. A303719. %K A303713 nonn %O A303713 1,3 %A A303713 _R. H. Hardin_, Apr 29 2018