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Number of n X n 0..1 arrays with no 1 equal to more than one of its horizontal and vertical neighbors, with the exception of exactly two elements.
0

%I #6 Apr 26 2020 20:42:03

%S 0,0,72,8536,2231690,1354321470,2028744947006,7685048253383394,

%T 74968472049231105434,1906199245553492643004970

%N Number of n X n 0..1 arrays with no 1 equal to more than one of its horizontal and vertical neighbors, with the exception of exactly two elements.

%C Diagonal of A283100.

%e Some solutions for n=4

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

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

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

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

%Y Cf. A283100.

%K nonn

%O 1,3

%A _R. H. Hardin_, Feb 28 2017