%I #9 Apr 15 2024 17:55:59
%S 1,0,2,35,1007,54819,4318217,458508379,62976460150,10860600443527,
%T 2297243685069637,584799993257765106
%N Number of n X 2 arrays containing 2 copies of 0..n-1 with no element 1 greater than its west or north neighbor modulo n and the upper left element equal to 0.
%C Column 2 of A266318.
%e Some solutions for n=4:
%e ..0..2....0..3....0..2....0..2....0..3....0..2....0..3....0..3....0..3....0..2
%e ..0..2....3..2....2..1....2..1....0..3....3..1....2..1....0..2....3..1....0..2
%e ..3..1....2..1....1..3....1..0....2..1....2..1....2..1....3..2....2..1....3..1
%e ..3..1....1..0....0..3....3..3....2..1....0..3....0..3....1..1....2..0....1..3
%Y Cf. A266318.
%K nonn,more
%O 1,3
%A _R. H. Hardin_, Dec 27 2015