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Number of nX4 arrays containing 4 indistinguishable copies of 1..n with rows and columns in lexicographically strictly increasing order
0

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

%S 1,1,472,300888,333191079,637698093267

%N Number of nX4 arrays containing 4 indistinguishable copies of 1..n with rows and columns in lexicographically strictly increasing order

%C Column 4 of A180839

%e Some solutions for 3X4

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

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

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

%e ...

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

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

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

%e ...

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

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

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

%K nonn

%O 1,3

%A _R. H. Hardin_ Sep 20 2010