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 A304005 #4 May 04 2018 11:19:12 %S A304005 1,7,13,21,27,53,99,197,371,713,1365,2645,5105,9857,19079,36861,71379, %T A304005 138165,267465,518201,1003521,1944649,3767939,7302057,14153291, %U A304005 27432325,53179669,103092661,199871009,387518385,751360183,1456897269,2824988675 %N A304005 Number of nX3 0..1 arrays with every element unequal to 0, 2, 3 or 5 king-move adjacent elements, with upper left element zero. %C A304005 Column 3 of A304010. %H A304005 R. H. Hardin, <a href="/A304005/b304005.txt">Table of n, a(n) for n = 1..210</a> %F A304005 Empirical: a(n) = a(n-1) +5*a(n-2) -a(n-3) -12*a(n-4) -2*a(n-5) +10*a(n-6) +2*a(n-7) +a(n-8) +7*a(n-9) -3*a(n-10) -19*a(n-11) -2*a(n-12) +2*a(n-13) -4*a(n-14) +10*a(n-15) +6*a(n-16) for n>17 %e A304005 Some solutions for n=5 %e A304005 ..0..1..0. .0..1..0. .0..0..0. .0..1..0. .0..0..0. .0..0..0. .0..0..0 %e A304005 ..0..1..1. .1..1..1. .0..0..0. .1..1..1. .1..1..1. .1..1..1. .0..0..0 %e A304005 ..1..0..0. .0..0..0. .0..0..0. .1..0..1. .1..1..1. .0..1..0. .0..0..0 %e A304005 ..1..1..0. .0..0..0. .0..0..0. .0..0..0. .1..1..1. .0..0..0. .1..1..1 %e A304005 ..0..1..0. .1..1..1. .1..1..1. .1..1..1. .0..0..0. .1..0..1. .0..1..0 %Y A304005 Cf. A304010. %K A304005 nonn %O A304005 1,2 %A A304005 _R. H. Hardin_, May 04 2018