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%I #7 Apr 12 2023 08:08:53
%S 0,1,8,36,456,6360,93600,1784160,38102400,899579520,23960966400,
%T 699741504000
%N Number of n X 3 arrays containing 3 copies of 0..n-1 with every element equal to at least one vertical or antidiagonal neighbor and the top left element equal to 0.
%C Column 3 of A268159.
%e Some solutions for n=4
%e ..0..0..2....0..0..1....0..0..2....0..0..2....0..1..1....0..0..1....0..3..3
%e ..0..1..2....0..1..2....0..2..1....0..2..3....0..1..3....0..1..3....0..3..1
%e ..1..2..3....1..3..2....2..1..3....2..1..3....0..3..2....1..3..2....0..2..1
%e ..1..3..3....3..3..2....1..3..3....1..1..3....3..2..2....3..2..2....2..2..1
%Y Cf. A268159.
%K nonn
%O 1,3
%A _R. H. Hardin_, Jan 27 2016
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