%I #5 Aug 12 2016 07:04:22
%S 1,0,1,7,351,19773,1567330,166758092,22928383502,3956915450846,
%T 837459080604863
%N Number of nX2 arrays containing 2 copies of 0..n-1 with no element 1 greater than its north, southwest or northwest neighbor modulo n and the upper left element equal to 0.
%C Column 2 of A266878.
%e All solutions for n=4
%e ..0..3....0..1....0..0....0..2....0..2....0..1....0..1
%e ..3..2....2..3....2..3....3..0....3..0....3..0....2..3
%e ..2..1....1..2....1..2....1..2....2..3....2..3....0..1
%e ..1..0....3..0....3..1....3..1....1..1....1..2....2..3
%Y Cf. A266878.
%K nonn
%O 1,4
%A _R. H. Hardin_, Jan 05 2016