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%I #4 Aug 12 2016 07:05:17
%S 1,4,340,56496,28645840,20091622560,29056095714720,52981034285587200,
%T 165795456023776938240
%N Number of nX3 arrays containing 3 copies of 0..n-1 with no element plus any antidiagonal neighbor equal to n-1.
%C Column 3 of A265870.
%e Some solutions for n=4
%e ..2..3..0....0..0..3....3..3..2....3..1..2....1..3..0....3..3..0....0..1..0
%e ..1..1..3....2..1..1....2..2..1....1..0..1....2..2..1....3..2..1....3..2..1
%e ..1..2..2....3..3..2....0..1..3....0..3..0....3..1..2....2..1..1....3..0..3
%e ..3..0..0....1..2..0....0..1..0....2..2..3....0..0..3....0..0..2....2..2..1
%Y Cf. A265870.
%K nonn
%O 1,2
%A _R. H. Hardin_, Dec 17 2015