A207881 - OEIS

%I #5 Mar 31 2012 12:37:20

%S 9,81,221,575,1673,4881,14825,45411,141381,443159,1399925,4442717,

%T 14159449,45263327,145061281,465794335,1498036809,4823779033,

%U 15548389529,50156459339,161898944109,522854621863,1689250105197,5459434154405

%N Number of nX4 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 1 1 and 1 1 0 vertically

%C Column 4 of A207885

%H R. H. Hardin, <a href="/A207881/b207881.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 8*a(n-1) -10*a(n-2) -67*a(n-3) +164*a(n-4) +194*a(n-5) -751*a(n-6) -172*a(n-7) +1630*a(n-8) -197*a(n-9) -1808*a(n-10) +490*a(n-11) +952*a(n-12) -320*a(n-13) -176*a(n-14) +64*a(n-15) for n>16

%e Some solutions for n=4

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Feb 21 2012