%I #5 Dec 18 2015 18:17:42
%S 0,2,20,855,107162,54992415,87587532068,474408802145495
%N Number of n X n symmetric 0..4 arrays with each element equal to the product mod 5 of two of its horizontal and vertical neighbors
%e Some solutions for 4X4
%e ..1..1..1..3....0..0..2..2....1..4..3..4....4..3..2..4....1..1..2..2
%e ..1..4..2..3....0..1..1..1....4..4..2..3....3..0..0..2....1..3..3..1
%e ..1..2..4..4....2..1..1..1....3..2..1..1....2..0..4..3....2..3..0..0
%e ..3..3..4..1....2..1..1..1....4..3..1..1....4..2..3..4....2..1..0..0
%K nonn
%O 1,2
%A _R. H. Hardin_ Jul 27 2011