%I #6 Dec 18 2015 18:18:54
%S 3,12,68,664,13672,560512,51483264,8726974464,3316077264896,
%T 2260633288966144,3463290521072435200,9453965541320232534016,
%U 58047351977461819763589120,633980080610711649347287646208
%N Number of n X n 0..2 arrays with the sum of the absolute differences of each element with its horizontal and vertical neighbors equal to the number of neighbors.
%C Diagonal of A265887.
%H R. H. Hardin, <a href="/A265886/b265886.txt">Table of n, a(n) for n = 1..18</a>
%e Some solutions for n=4
%e ..2..1..2..2....0..0..1..0....1..2..1..0....1..2..1..2....2..1..0..1
%e ..1..2..0..0....2..2..0..1....2..1..2..1....0..1..2..1....1..2..1..2
%e ..2..2..0..1....1..2..0..2....1..2..1..0....1..2..1..0....2..1..2..1
%e ..0..0..1..2....0..1..0..2....0..1..0..1....2..1..0..1....1..2..1..2
%Y Cf. A265887.
%K nonn
%O 1,1
%A _R. H. Hardin_, Dec 17 2015