A266992 Number of nX2 arrays containing 2 copies of 0..n-1 with no element 1 greater than its west, northeast or northwest neighbor modulo n and the upper left element equal to 0.

1, 0, 2, 23, 907, 51499, 4161843, 447189962, 61857780853, 10715103899514, 2273223334188772

Offset

1,3

Comments

Column 2 of A266994.

Links

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

Example

Some solutions for n=6
..0..4....0..2....0..2....0..4....0..3....0..5....0..4....0..3....0..0....0..0
..4..2....1..3....0..4....2..4....5..2....3..0....2..0....3..2....3..5....2..4
..0..3....5..3....3..5....3..5....0..4....3..2....5..2....5..1....5..2....1..4
..1..3....2..4....4..2....3..0....1..3....5..2....1..3....4..1....4..3....3..1
..2..1....0..5....1..1....5..2....5..4....1..4....5..4....0..2....2..1....3..5
..5..5....1..4....5..3....1..1....2..1....4..1....3..1....5..4....4..1....2..5

Crossrefs

Cf. A266994.

Sequence in context: A098633 A015211 A378113 * A079480 A239398 A239811

Adjacent sequences: A266989 A266990 A266991 * A266993 A266994 A266995

Keyword

nonn

Author

R. H. Hardin, Jan 08 2016

Status

approved