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 A303715 #4 Apr 29 2018 10:52:06 %S A303715 5,5,8,17,36,76,161,349,749,1604,3449,7412,15912,34177,73421,157693, %T A303715 338696,727505,1562612,3356300,7209009,15484261,33258581,71436052, %U A303715 153437513,329568260,707879240,1520453249,3265780149,7014565813 %N A303715 Number of nX4 0..1 arrays with every element unequal to 0, 1 or 5 king-move adjacent elements, with upper left element zero. %C A303715 Column 4 of A303719. %H A303715 R. H. Hardin, <a href="/A303715/b303715.txt">Table of n, a(n) for n = 1..210</a> %F A303715 Empirical: a(n) = a(n-1) +a(n-2) +3*a(n-3) +a(n-4) -a(n-5) -a(n-6) %e A303715 Some solutions for n=5 %e A303715 ..0..0..0..0. .0..0..0..0. .0..1..0..0. .0..0..1..0. .0..0..0..0 %e A303715 ..0..0..0..0. .1..0..0..1. .0..0..0..0. .0..0..0..0. .0..0..0..0 %e A303715 ..1..0..0..1. .0..0..0..0. .0..0..0..0. .0..0..0..0. .0..0..0..1 %e A303715 ..0..0..0..0. .0..0..0..0. .0..0..0..1. .0..0..0..0. .1..0..0..0 %e A303715 ..0..0..0..0. .0..0..1..0. .0..0..0..0. .0..1..0..0. .0..0..0..0 %Y A303715 Cf. A303719. %K A303715 nonn %O A303715 1,1 %A A303715 _R. H. Hardin_, Apr 29 2018