The OEIS is supported by the many generous donors to the OEIS Foundation.
%I #5 Aug 12 2016 07:04:21
%S 0,0,0,16,1528,71328,10109856,949116288,197260755456,30713652142080,
%T 8957030720294400,2091857665680783360
%N Number of nX2 arrays containing 2 copies of 0..n-1 with no element plus any horizontal, vertical or antidiagonal neighbor equal to n-1.
%C Column 2 of A266158.
%e Some solutions for n=6
%e ..0..1....5..5....5..3....0..2....0..1....1..1....0..1....0..4....5..5....3..1
%e ..2..2....1..1....3..5....4..0....0..3....0..3....2..5....2..2....3..1....0..0
%e ..5..1....2..2....4..4....4..3....3..1....4..5....4..4....5..1....1..0....2..2
%e ..3..5....4..0....0..2....5..5....5..5....5..2....2..5....5..1....2..2....4..4
%e ..3..4....0..3....0..2....2..1....2..4....2..4....1..3....3..0....4..0....5..3
%e ..4..0....4..3....1..1....1..3....2..4....0..3....0..3....4..3....4..3....1..5
%Y Cf. A266158.
%K nonn
%O 1,4
%A _R. H. Hardin_, Dec 22 2015