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 A298920 #6 Sep 04 2022 13:19:04 %S A298920 1,8,2,3,7,6,9,20,22,35,59,90,145,240,378,611,991,1598,2585,4188,6766, %T A298920 10947,17715,28658,46369,75032,121394,196419,317815,514230,832041, %U A298920 1346276,2178310,3524579,5702891,9227466,14930353,24157824,39088170 %N A298920 Number of n X 4 0..1 arrays with every element equal to 1, 3, 5, 7 or 8 king-move adjacent elements, with upper left element zero. %C A298920 Column 4 of A298924. %H A298920 R. H. Hardin, <a href="/A298920/b298920.txt">Table of n, a(n) for n = 1..210</a> %F A298920 Empirical: a(n) = a(n-1) +a(n-2) +a(n-6) -a(n-7) -a(n-8). %e A298920 Some solutions for n=5 %e A298920 ..0..0..0..0. .0..1..0..1. .0..0..0..0. .0..0..0..0. .0..0..1..1 %e A298920 ..0..0..0..0. .0..1..0..1. .0..0..0..0. .0..0..0..0. .0..0..1..1 %e A298920 ..1..1..1..1. .1..1..0..0. .0..0..0..0. .0..0..0..0. .0..0..1..1 %e A298920 ..1..1..1..1. .0..1..0..1. .1..1..1..1. .0..0..0..0. .0..0..1..1 %e A298920 ..1..1..1..1. .0..1..0..1. .1..1..1..1. .0..0..0..0. .0..0..1..1 %Y A298920 Cf. A298924. %K A298920 nonn %O A298920 1,2 %A A298920 _R. H. Hardin_, Jan 29 2018