A208072 - OEIS

%I #5 Mar 31 2012 12:37:21

%S 20,400,432,2688,11424,44064,198000,844800,3542544,15213984,64859616,

%T 275633280,1175819856,5010674496,21340192176,90942560256,387500834976,

%U 1650940063776,7034502996720,29972774288640,127706156346384

%N Number of 7Xn 0..1 arrays avoiding 0 0 0 and 1 1 1 horizontally and 0 0 1 and 0 1 1 vertically

%C Row 7 of A208069

%H R. H. Hardin, <a href="/A208072/b208072.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = a(n-1) +4*a(n-2) +39*a(n-3) +20*a(n-4) +19*a(n-5) -191*a(n-6) -42*a(n-7) -36*a(n-8) +216*a(n-9) for n>11

%e Some solutions for n=4

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

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

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

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Feb 23 2012