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 A302742 #4 Apr 12 2018 11:22:39 %S A302742 4,32,228,1637,11814,85268,615589,4444226,32085336,231641898, %T A302742 1672352613,12073650477,87166448968,629303444781,4543294244531, %U A302742 32800587324576,236805822155030,1709633941974433,12342805548255732,89109630466361141 %N A302742 Number of 3Xn 0..1 arrays with every element equal to 0, 1, 2, 3 or 4 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. %C A302742 Row 3 of A302741. %H A302742 R. H. Hardin, <a href="/A302742/b302742.txt">Table of n, a(n) for n = 1..210</a> %F A302742 Empirical: a(n) = 7*a(n-1) +4*a(n-2) -17*a(n-3) -3*a(n-4) -9*a(n-6) +14*a(n-7) for n>8 %e A302742 Some solutions for n=5 %e A302742 ..0..0..1..0..1. .0..0..1..1..0. .0..1..0..1..0. .0..1..0..0..1 %e A302742 ..1..1..0..1..1. .1..0..0..1..0. .1..0..0..0..1. .0..1..0..1..0 %e A302742 ..0..1..1..0..0. .0..1..1..0..1. .1..1..0..0..1. .1..1..1..0..1 %Y A302742 Cf. A302741. %K A302742 nonn %O A302742 1,1 %A A302742 _R. H. Hardin_, Apr 12 2018