%I #7 Dec 02 2021 18:17:09
%S 3,27,729,59240,14349636,10460353203,22876792454961,
%T 150094635296999121,2954312847295467367104
%N Number of n X n symmetric 0..3 arrays with no element equal to the sum mod 4 of all its horizontal and vertical neighbors.
%e Some solutions for 4 X 4
%e ..0..1..3..3....1..1..2..2....0..3..3..2....0..3..2..0....1..0..2..3
%e ..1..3..1..2....1..1..1..1....3..1..1..2....3..0..2..0....0..0..1..3
%e ..3..1..3..3....2..1..2..1....3..1..1..1....2..2..2..0....2..1..1..1
%e ..3..2..3..3....2..1..1..3....2..2..1..3....0..0..0..3....3..3..1..3
%K nonn
%O 1,1
%A _R. H. Hardin_, Jul 31 2011