A266468 Number of nX6 binary arrays with rows and columns lexicographically nondecreasing and column sums nonincreasing.

2, 8, 39, 261, 2090, 18808, 175180, 1595005, 13720886, 109830369, 814603355, 5605474331, 35922351069, 215377645103, 1213816837380, 6458765687442, 32580784869691, 156385330035183, 716642920656832

Offset

1,1

Comments

Column 6 of A266470.

Links

Table of n, a(n) for n=1..19.

Example

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

Crossrefs

Cf. A266470.

Sequence in context: A307709 A217945 A091073 * A326963 A306781 A154132

Adjacent sequences: A266465 A266466 A266467 * A266469 A266470 A266471

Keyword

nonn

Author

R. H. Hardin, Dec 29 2015

Status

approved