A266823 Number of nX2 arrays containing 2 copies of 0..n-1 with no element 1 greater than its north, west, northwest or southwest neighbor modulo n and the upper left element equal to 0.

1, 0, 0, 1, 86, 4701, 378116, 41728537, 5954780104, 1062483996748, 231414064262143

Offset

1,5

Comments

Column 2 of A266825.

Links

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

Example

Some solutions for n=5
..0..3....0..0....0..2....0..2....0..4....0..2....0..0....0..0....0..2....0..2
..0..3....2..2....4..4....4..2....4..3....0..4....2..4....2..2....2..0....2..4
..4..2....4..4....1..3....4..1....3..1....4..2....1..1....4..1....1..4....4..1
..2..1....1..1....3..1....1..3....2..1....3..1....4..3....1..3....4..3....1..3
..4..1....3..3....2..0....0..3....2..0....3..1....3..2....4..3....3..1....3..0

Crossrefs

Cf. A266825.

Sequence in context: A035738 A017749 A319134 * A262471 A223739 A223722

Adjacent sequences: A266820 A266821 A266822 * A266824 A266825 A266826

Keyword

nonn

Author

R. H. Hardin, Jan 04 2016

Status

approved