A228684 - OEIS

%I #10 Sep 12 2018 12:04:10

%S 8,17,77,216,809,2529,8832,28793,97933,324464,1092561,3642241,

%T 12217528,40825697,136745357,457357256,1531058169,5122533089,

%U 17144628912,57369165513,191993439053,642478726624,2150072260001,7195049684481

%N Number of 3 X n binary arrays with no two ones adjacent horizontally, diagonally or antidiagonally.

%H R. H. Hardin, <a href="/A228684/b228684.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 2*a(n-1) + 6*a(n-2) - 5*a(n-3).

%F Empirical g.f.: x*(8 + x - 5*x^2) / (1 - 2*x - 6*x^2 + 5*x^3). - _Colin Barker_, Sep 12 2018

%e Some solutions for n=4:

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

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

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

%Y Row 3 of A228683.

%K nonn

%O 1,1

%A _R. H. Hardin_, Aug 30 2013