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 A302009 #4 Mar 30 2018 12:52:14 %S A302009 64,8192,772272,75450768,7350348800,716213306576,69786476414080, %T A302009 6799869079320928,662567007297568064,64559337205664347760, %U A302009 6290545670866971762128,612939453077470915120704 %N A302009 Number of nX7 0..1 arrays with every element equal to 0, 1, 2 or 3 horizontally or antidiagonally adjacent elements, with upper left element zero. %C A302009 Column 7 of A302010. %H A302009 R. H. Hardin, <a href="/A302009/b302009.txt">Table of n, a(n) for n = 1..210</a> %F A302009 Empirical: a(n) = 85*a(n-1) +1213*a(n-2) +405*a(n-3) -48433*a(n-4) -99541*a(n-5) +739091*a(n-6) +1518593*a(n-7) -5898671*a(n-8) -5217125*a(n-9) +25830080*a(n-10) -16620026*a(n-11) -10284072*a(n-12) +13380888*a(n-13) -2391872*a(n-14) -1786496*a(n-15) +844032*a(n-16) -105472*a(n-17) for n>19 %e A302009 Some solutions for n=5 %e A302009 ..0..0..0..0..1..1..1. .0..0..0..0..1..1..1. .0..0..0..0..1..1..1 %e A302009 ..0..0..1..0..0..0..0. .0..0..1..0..0..0..1. .0..0..1..0..0..0..1 %e A302009 ..0..0..0..1..1..1..1. .0..0..0..1..0..0..1. .0..0..0..1..0..1..0 %e A302009 ..0..0..1..0..0..0..1. .0..0..1..0..1..1..0. .0..0..1..1..1..0..1 %e A302009 ..0..0..0..0..1..0..1. .0..0..0..1..0..1..1. .0..0..0..0..0..0..0 %Y A302009 Cf. A302010. %K A302009 nonn %O A302009 1,1 %A A302009 _R. H. Hardin_, Mar 30 2018