A228386 - OEIS

%I #10 Sep 11 2018 05:41:10

%S 3,12,72,382,2104,11449,62546,341249,1862631,10165343,55480071,

%T 302792766,1652555713,9019158650,49223917246,268649627276,

%U 1466210540982,8002145144295,43673350799304,238356282199103,1300878367732021

%N Number of n X 4 binary arrays with top left value 1 and no two ones adjacent horizontally or vertically.

%H R. H. Hardin, <a href="/A228386/b228386.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 4*a(n-1) +9*a(n-2) -5*a(n-3) -4*a(n-4) +a(n-5).

%F Empirical g.f.: x*(3 - 3*x^2 + x^3) / (1 - 4*x - 9*x^2 + 5*x^3 + 4*x^4 - x^5). - _Colin Barker_, Sep 11 2018

%e Some solutions for n=4:

%e ..1..0..0..0....1..0..1..0....1..0..1..0....1..0..1..0....1..0..1..0

%e ..0..1..0..0....0..0..0..1....0..1..0..1....0..1..0..1....0..0..0..0

%e ..1..0..1..0....1..0..1..0....0..0..0..0....1..0..1..0....1..0..1..0

%e ..0..0..0..0....0..1..0..0....0..1..0..1....0..0..0..0....0..1..0..1

%Y Column 4 of A228390.

%K nonn

%O 1,1

%A _R. H. Hardin_, Aug 21 2013