A266919 Number of nX2 arrays containing 2 copies of 0..n-1 with no element 1 greater than its north, southwest or southeast neighbor modulo n and the upper left element equal to 0.

1, 0, 4, 23, 398, 23432, 1841274, 193070360, 26165335486, 4456558300940, 932617500467182

Offset

1,3

Comments

Column 2 of A266921.

Links

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

Example

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

Crossrefs

Cf. A266921.

Sequence in context: A303652 A130890 A219932 * A219464 A107765 A304413

Adjacent sequences: A266916 A266917 A266918 * A266920 A266921 A266922

Keyword

nonn

Author

R. H. Hardin, Jan 06 2016

Status

approved