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%I #10 Aug 11 2015 17:41:04
%S 1,18,588,30240,2277600,234440280,31448589480
%N Number of n X 3 nonnegative integer arrays with new values 0 upwards introduced in row major order and every value unique in its row and column.
%C Column 3 of A211709.
%e Some solutions for n=4:
%e ..0..1..2....0..1..2....0..1..2....0..1..2....0..1..2....0..1..2....0..1..2
%e ..2..3..0....1..3..0....1..0..3....3..0..1....1..0..3....1..0..3....1..0..3
%e ..1..2..3....2..0..1....2..3..0....1..2..0....3..2..1....2..3..4....2..3..1
%e ..3..0..1....3..4..5....3..2..1....2..3..4....2..3..0....3..5..6....3..2..0
%K nonn
%O 1,2
%A _R. H. Hardin_, Apr 19 2012