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1/3 the number of nX7 0..2 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors
0

%I #6 Mar 31 2012 12:36:02

%S 21,13256,2792166,684657326,160107914496,38323943289566,

%T 9079893278572272,2159859526859795892

%N 1/3 the number of nX7 0..2 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors

%C Column 7 of A185559

%e Some solutions for 4X7 with a(1,1)=0

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Jan 31 2011