%I #5 Mar 31 2012 12:36:34

%S 36,2436,162776,10937316,734979136,49393306556,3319433387656,

%T 223079838087956,14991902921730896,1007518927448282476,

%U 67709509526621985176,4550363827896811116996,305803588199889010224736

%N Number of 2nX4 0..2 arrays with values 0..2 introduced in row major order and each element equal to an even number of horizontal and vertical neighbors

%C Column 2 of A198642

%H R. H. Hardin, <a href="/A198639/b198639.txt">Table of n, a(n) for n = 1..200</a>

%F Empirical: a(n) = 78*a(n-1) -569*a(n-2) -11744*a(n-3) +71840*a(n-4) +745984*a(n-5) -2507008*a(n-6) -18538496*a(n-7) +36110336*a(n-8) +142606336*a(n-9) -268435456*a(n-10)

%e Some solutions for n=3

%e ..0..1..0..2....0..1..0..1....0..1..0..1....0..1..0..1....0..1..0..1

%e ..1..0..1..0....1..0..1..0....1..0..2..0....1..0..1..0....1..0..2..0

%e ..2..1..2..1....2..2..0..1....2..1..0..1....2..1..0..1....2..1..0..1

%e ..1..2..1..2....2..2..1..0....0..2..1..2....1..2..1..0....1..2..1..2

%e ..2..0..2..0....0..1..2..1....2..1..2..0....0..1..0..2....2..1..0..1

%e ..1..2..0..1....1..0..1..0....0..2..1..2....1..0..2..1....1..2..1..2

%K nonn

%O 1,1

%A _R. H. Hardin_ Oct 27 2011