A207270 - OEIS

%I #5 Mar 31 2012 12:37:16

%S 6,36,82,217,499,1014,2141,4188,8150,15670,29517,55523,103348,191593,

%T 353916,651316,1196664,2193747,4017137,7347906,13429145,24530862,

%U 44784850,81739060,149141623,272067741,496250336,905026713,1650411906

%N Number of 3Xn 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 1 1 and 1 0 1 vertically

%C Row 3 of A207269

%H R. H. Hardin, <a href="/A207270/b207270.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = a(n-1) +4*a(n-2) +2*a(n-3) -12*a(n-4) -9*a(n-5) +6*a(n-6) +20*a(n-7) +6*a(n-8) -2*a(n-9) -16*a(n-10) -12*a(n-11) -4*a(n-12) +14*a(n-13) +9*a(n-14) +a(n-15) -6*a(n-16) -2*a(n-17) +a(n-19)

%e Some solutions for n=4

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Feb 16 2012