A266630 Number of nX2 arrays containing 2 copies of 0..n-1 with no element 1 greater than its north, west, southeast or southwest neighbor modulo n and the upper left element equal to 0.

1, 0, 1, 13, 139, 7623, 585112, 60695930, 8247622671, 1413690625856, 298076685938894

Offset

1,4

Comments

Column 2 of A266632.

Links

Table of n, a(n) for n=1..11.

Example

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

Crossrefs

Cf. A266632.

Sequence in context: A195464 A365999 A064103 * A186506 A051639 A138931

Adjacent sequences: A266627 A266628 A266629 * A266631 A266632 A266633

Keyword

nonn

Author

R. H. Hardin, Jan 01 2016

Status

approved