A220748 - OEIS

%I #5 Dec 18 2012 18:26:22

%S 4,38,395,3778,32178,261356,2096110,16776148,134216342,1073740504,

%T 8589932829,68719475152,549755811711,4398046509244,35184372086204,

%U 281474976708508,2251799813682132,18014398509479536,144115188075852231

%N Equals one maps: number of nX3 binary arrays indicating the locations of corresponding elements equal to exactly one of their horizontal and vertical neighbors in a random 0..3 nX3 array

%C Column 3 of A220751

%H R. H. Hardin, <a href="/A220748/b220748.txt">Table of n, a(n) for n = 1..59</a>

%F Empirical: a(n) = 8*a(n-1) +3*a(n-2) -24*a(n-3) -3*a(n-4) +24*a(n-5) +a(n-6) -8*a(n-7) for n>14

%e Some solutions for n=3

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Dec 18 2012