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%I #5 Aug 12 2016 07:04:22
%S 1,3,11,54,330,2430,20970,207900,2331000,29189160,404044200,
%T 6129723600,101181603600,1805933329200,34664949118800
%N Number of nX2 arrays containing 2 copies of 0..n-1 with every element equal to or 1 greater than any northeast neighbor modulo n and the upper left element equal to 0.
%C Column 2 of A267836.
%e Some solutions for n=4
%e ..0..1....0..1....0..3....0..0....0..1....0..3....0..2....0..3....0..2....0..1
%e ..2..3....2..2....3..1....1..2....1..3....3..2....2..3....0..1....2..3....2..3
%e ..0..1....3..0....1..2....3..2....0..2....2..0....3..0....2..1....0..1....3..0
%e ..2..3....1..3....2..0....3..1....2..3....1..1....1..1....2..3....1..3....1..2
%Y Cf. A267836.
%K nonn
%O 1,2
%A _R. H. Hardin_, Jan 21 2016