A278722 Number of nX3 0..3 arrays with rows in nondecreasing lexicographic order and columns in nonincreasing lexicographic order.

20, 275, 3232, 33466, 306070, 2487889, 18151220, 120104810, 727684612, 4070893254, 21181152380, 103146867706, 472709673984, 2048611972127, 8431440391174, 33079800818118, 124138709933301, 446936241587393

Offset

1,1

Comments

Column 3 of A278727.

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

R. H. Hardin, Empirical polynomial of degree 45

Formula

Empirical polynomial of degree 45 (see link above)

Example

Some solutions for n=4
..0..0..0. .2..0..0. .1..0..0. .1..0..0. .2..1..0. .1..0..0. .1..1..0
..1..1..0. .2..1..1. .2..0..0. .1..3..2. .2..1..0. .1..1..0. .2..1..0
..2..2..2. .2..2..2. .3..2..1. .3..1..3. .2..1..2. .2..2..3. .2..3..3
..3..0..2. .2..2..2. .3..3..1. .3..3..2. .2..3..3. .3..3..0. .3..1..0

Crossrefs

Cf. A278727.

Sequence in context: A019613 A021514 A121117 * A021264 A025928 A004334

Adjacent sequences: A278719 A278720 A278721 * A278723 A278724 A278725

Keyword

nonn

Author

R. H. Hardin, Nov 27 2016

Status

approved