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 A302304 #4 Apr 05 2018 09:34:58 %S A302304 3,11,13,33,58,153,336,937,2449,6560,18488,52053,147896,425764, %T A302304 1229112,3561761,10353391,30135225,87835075,256217794,747737289, %U A302304 2183170380,6375689391,18622164403,54399493814,158924553086,464309179701 %N A302304 Number of nX3 0..1 arrays with every element equal to 0, 1, 3 or 4 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. %C A302304 Column 3 of A302309. %H A302304 R. H. Hardin, <a href="/A302304/b302304.txt">Table of n, a(n) for n = 1..210</a> %F A302304 Empirical: a(n) = 3*a(n-1) -2*a(n-2) +13*a(n-3) -23*a(n-4) +13*a(n-5) -42*a(n-6) +25*a(n-7) -21*a(n-8) -36*a(n-9) +48*a(n-10) -24*a(n-11) +8*a(n-12) +32*a(n-13) for n>16 %e A302304 Some solutions for n=5 %e A302304 ..0..1..0. .0..1..0. .0..1..1. .0..1..0. .0..1..0. .0..0..1. .0..1..0 %e A302304 ..1..1..0. .0..1..0. .1..0..1. .1..1..0. .0..1..0. .0..1..0. .1..1..0 %e A302304 ..1..1..1. .0..1..0. .0..0..0. .0..1..0. .1..1..0. .1..1..1. .1..1..1 %e A302304 ..1..1..0. .0..1..1. .0..0..1. .0..1..0. .0..1..0. .0..1..1. .0..1..0 %e A302304 ..0..1..0. .0..1..0. .1..0..1. .1..0..0. .0..0..0. .0..1..0. .1..0..0 %Y A302304 Cf. A302309. %K A302304 nonn %O A302304 1,1 %A A302304 _R. H. Hardin_, Apr 05 2018