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 A301960 #4 Mar 29 2018 12:59:22 %S A301960 5,9,25,64,169,441,1156,3025,7921,20736,54289,142129,372100,974169, %T A301960 2550409,6677056,17480761,45765225,119814916,313679521,821223649, %U A301960 2149991424,5628750625,14736260449,38580030724,101003831721,264431464441 %N A301960 Number of nX4 0..1 arrays with every element equal to 0, 1 or 4 horizontally or antidiagonally adjacent elements, with upper left element zero. %C A301960 Column 4 of A301964. %H A301960 R. H. Hardin, <a href="/A301960/b301960.txt">Table of n, a(n) for n = 1..210</a> %F A301960 Empirical: a(n) = 2*a(n-1) +2*a(n-2) -a(n-3) for n>4 %e A301960 Some solutions for n=5 %e A301960 ..0..0..1..0. .0..1..1..0. .0..0..1..0. .0..1..0..1. .0..1..0..1 %e A301960 ..1..1..1..0. .0..0..1..0. .1..1..1..0. .0..1..1..1. .0..1..0..1 %e A301960 ..1..0..1..0. .1..0..1..0. .1..0..1..1. .0..1..0..1. .1..0..1..0 %e A301960 ..1..0..0..0. .1..0..1..0. .1..0..0..1. .0..0..0..1. .1..0..1..1 %e A301960 ..1..0..1..1. .1..0..1..0. .1..1..0..0. .0..1..0..0. .1..0..0..1 %Y A301960 Cf. A301964. %K A301960 nonn %O A301960 1,1 %A A301960 _R. H. Hardin_, Mar 29 2018