A269477 Number of nX2 arrays containing 2 copies of 0..n-1 avoiding the pattern down-up in every row and equal-up in every column.

1, 6, 54, 600, 9102, 188472, 5118012, 172101936, 6887210886, 321643938456

Offset

1,2

Comments

Column 2 of A269479.

Links

Table of n, a(n) for n=1..10.

Example

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

Crossrefs

Cf. A269479.

Sequence in context: A186375 A231554 A069726 * A305602 A367471 A367475

Adjacent sequences: A269474 A269475 A269476 * A269478 A269479 A269480

Keyword

nonn

Author

R. H. Hardin, Feb 27 2016

Status

approved