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 A228477 #10 Sep 01 2013 17:50:07 %S A228477 2,4,14,41,127,386,1181,3605,11013,33635,102734,313780,958385,2927208, %T A228477 8940618,27307464,83405606,254747013,778077691,2376494562,7258563605, %U A228477 22169941573,67713990833,206819875427,631693101322,1929389878184 %N A228477 Number of nX3 binary arrays with top left value 1 and no two ones adjacent horizontally, vertically or antidiagonally. %C A228477 Column 3 of A228482 %C A228477 Same recurrences as A228285 except in addition a smaller one for column 5 %H A228477 R. H. Hardin, <a href="/A228477/b228477.txt">Table of n, a(n) for n = 1..210</a> %F A228477 a(n) = a(n-1) +5*a(n-2) +4*a(n-3) -a(n-5). %F A228477 G.f.: -x*(-2-2*x+x^3) / ( (1+x)*(x^4-x^3-3*x^2-2*x+1) ). - _R. J. Mathar_, Aug 25 2013 %e A228477 Some solutions for n=4 %e A228477 ..1..0..1....1..0..1....1..0..0....1..0..0....1..0..0....1..0..0....1..0..0 %e A228477 ..0..0..0....0..0..0....0..1..0....0..0..1....0..0..0....0..0..0....0..0..1 %e A228477 ..1..0..1....0..0..0....0..0..0....1..0..0....1..0..1....0..0..0....1..0..0 %e A228477 ..0..0..0....0..0..0....1..0..0....0..0..0....0..0..0....0..0..0....0..0..1 %K A228477 nonn %O A228477 1,1 %A A228477 _R. H. Hardin_ Aug 22 2013