A180838 Number of nX4 arrays containing 4 indistinguishable copies of 1..n with rows and columns in lexicographically strictly increasing order

1, 1, 472, 300888, 333191079, 637698093267

Offset

1,3

Comments

Column 4 of A180839

Links

Table of n, a(n) for n=1..6.

Example

Some solutions for 3X4
..1..1..1..2....1..1..1..2....1..1..1..2....1..1..1..2....1..1..1..2
..1..2..3..2....1..2..3..3....1..2..3..3....1..2..3..3....1..2..3..2
..2..3..3..3....2..2..3..3....2..3..3..2....2..3..2..3....3..2..3..3
...
..1..1..1..2....1..1..1..2....1..1..1..2....1..1..1..2....1..1..1..2
..1..2..3..2....1..2..3..2....1..2..2..3....1..2..3..3....1..2..3..3
..3..3..3..2....3..3..2..3....3..2..3..3....3..2..3..2....3..2..2..3
...
..1..1..1..2....1..1..1..2....1..1..1..2....1..1..1..2....1..1..2..2
..1..2..3..3....1..3..3..2....1..3..3..3....1..3..3..2....1..1..2..3
..3..3..2..2....2..2..3..3....2..2..3..2....3..2..3..2....2..3..3..3

Crossrefs

Sequence in context: A259640 A187161 A249534 * A006180 A074654 A157434

Adjacent sequences: A180835 A180836 A180837 * A180839 A180840 A180841

Keyword

nonn

Author

R. H. Hardin Sep 20 2010

Status

approved