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Number of nX3 arrays containing 3 indistinguishable copies of 1..n with lexicographical ordering of rows strictly increasing and columns strictly decreasing
0

%I #2 Mar 31 2012 12:35:48

%S 1,1,19,596,37423,3746117,545626043,109162526742,28754907355070

%N Number of nX3 arrays containing 3 indistinguishable copies of 1..n with lexicographical ordering of rows strictly increasing and columns strictly decreasing

%C Column 3 of A180843

%e All solutions for 3X3

%e ..1..1..1....2..1..1....2..1..1....2..1..1....2..1..1....2..1..1....2..1..1

%e ..3..2..2....2..2..1....2..3..1....2..3..1....2..3..1....2..3..2....2..3..2

%e ..3..3..2....3..3..3....2..3..3....3..3..2....3..2..3....3..3..1....3..1..3

%e ...

%e ..2..1..1....2..1..1....2..1..1....2..1..1....2..2..1....2..2..1....2..2..1

%e ..2..3..3....3..2..1....3..2..1....3..2..2....3..1..1....3..1..1....3..1..2

%e ..3..2..1....3..3..2....3..2..3....3..3..1....3..3..2....3..2..3....3..3..1

%e ...

%e ..2..2..1....2..2..1....2..2..1....2..2..2....3..1..1

%e ..3..1..2....3..1..3....3..2..1....3..1..1....3..2..1

%e ..3..1..3....3..2..1....3..3..1....3..3..1....3..2..2

%K nonn

%O 1,3

%A _R. H. Hardin_ Sep 20 2010