%I #5 Aug 12 2016 07:04:22
%S 1,0,1,13,331,17651,1386377,148410280,20588092054,3584553946578,
%T 764734875953730,196150243865801221
%N Number of nX2 arrays containing 2 copies of 0..n-1 with no element 1 greater than its north, west or southwest neighbor modulo n and the upper left element equal to 0.
%C Column 2 of A266904.
%e Some solutions for n=6
%e ..0..4....0..3....0..2....0..2....0..5....0..4....0..2....0..2....0..2....0..4
%e ..4..1....4..1....0..5....3..2....0..3....5..1....3..1....4..1....2..1....4..1
%e ..3..0....1..5....2..4....0..4....5..2....4..0....3..5....3..5....5..3....1..5
%e ..3..5....5..2....5..3....5..3....3..1....1..3....0..4....1..3....5..3....3..3
%e ..2..1....3..0....4..1....4..1....1..4....3..2....5..4....4..2....4..0....0..2
%e ..2..5....2..4....1..3....1..5....4..2....2..5....2..1....0..5....1..4....5..2
%Y Cf. A266904.
%K nonn
%O 1,4
%A _R. H. Hardin_, Jan 05 2016