A266289 Number of nX2 arrays containing 2 copies of 0..n-1 with no element 1 greater than its north, west or northeast neighbor modulo n and the upper left element equal to 0.

1, 0, 2, 9, 435, 20375, 1624164, 170338575, 23301045360, 4006433553814, 845857620264286, 215056002391454266

Offset

1,3

Comments

Column 2 of A266291.

Links

Table of n, a(n) for n=1..12.

Example

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

Crossrefs

Cf. A266291.

Sequence in context: A325619 A049299 A024225 * A000883 A086693 A085605

Adjacent sequences: A266286 A266287 A266288 * A266290 A266291 A266292

Keyword

nonn

Author

R. H. Hardin, Dec 26 2015

Status

approved