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 A302011 #6 Apr 23 2021 11:31:23 %S A302011 8,128,1808,25808,369040,5276816,75450768,1078839952,15425887120, %T A302011 220568403088,3153816694160,45095125134992,644796609413008, %U A302011 9219680980164752,131828418659815824,1884960228421653136 %N A302011 Number of 4 X n 0..1 arrays with every element equal to 0, 1, 2 or 3 horizontally or antidiagonally adjacent elements, with upper left element zero. %C A302011 Row 4 of A302010. %H A302011 R. H. Hardin, <a href="/A302011/b302011.txt">Table of n, a(n) for n = 1..210</a> %F A302011 Empirical: a(n) = 13*a(n-1) +20*a(n-2) -16*a(n-3) -64*a(n-4) for n > 6. %e A302011 Some solutions for n=5 %e A302011 ..0..0..1..0..0. .0..0..1..0..0. .0..1..0..0..1. .0..1..1..1..0 %e A302011 ..0..1..0..1..1. .0..0..1..1..0. .0..1..0..0..0. .0..1..0..1..0 %e A302011 ..0..1..0..1..1. .0..0..0..0..1. .0..0..1..0..1. .0..1..1..1..1 %e A302011 ..1..0..1..0..1. .0..1..0..0..0. .0..0..1..0..0. .0..0..1..0..0 %Y A302011 Cf. A302010. %K A302011 nonn %O A302011 1,1 %A A302011 _R. H. Hardin_, Mar 30 2018