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 A302804 #4 Apr 13 2018 13:06:05 %S A302804 8,105,934,8718,82367,773520,7267160,68346451,642498696,6040048126, %T A302804 56785892353,533860095036,5018978504768,47185161079295, %U A302804 443603218392484,4170460416343998,39207890434190925,368606418000678668 %N A302804 Number of nX4 0..1 arrays with every element equal to 0, 1, 2, 3 or 5 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. %C A302804 Column 4 of A302808. %H A302804 R. H. Hardin, <a href="/A302804/b302804.txt">Table of n, a(n) for n = 1..210</a> %F A302804 Empirical: a(n) = 10*a(n-1) +a(n-2) +25*a(n-3) -853*a(n-4) -99*a(n-5) +2046*a(n-6) +16917*a(n-7) -2302*a(n-8) -31502*a(n-9) -89718*a(n-10) +14428*a(n-11) +54836*a(n-12) -37484*a(n-13) +150384*a(n-14) -43524*a(n-15) +14472*a(n-16) -33696*a(n-17) +5832*a(n-18) for n>20 %e A302804 Some solutions for n=5 %e A302804 ..0..1..1..0. .0..1..1..1. .0..1..0..0. .0..0..1..1. .0..1..1..0 %e A302804 ..1..0..1..1. .0..0..1..0. .0..1..1..0. .1..0..1..1. .0..1..0..1 %e A302804 ..1..0..1..1. .1..0..0..0. .0..0..1..1. .1..0..0..1. .1..0..1..0 %e A302804 ..0..1..1..0. .1..0..0..1. .1..1..0..0. .0..1..1..0. .1..0..0..1 %e A302804 ..0..0..0..1. .1..0..0..0. .0..1..1..1. .1..1..0..0. .1..1..0..1 %Y A302804 Cf. A302808. %K A302804 nonn %O A302804 1,1 %A A302804 _R. H. Hardin_, Apr 13 2018