A266492 Number of nX2 arrays containing 2 copies of 0..n-1 with no element 1 greater than its north, west, northwest or northeast neighbor modulo n and the upper left element equal to 0.

1, 0, 1, 4, 187, 7400, 573865, 58849205, 8029423880, 1380758051751, 292145368826808

Offset

1,4

Comments

Column 2 of A266493.

Links

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

Example

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

Crossrefs

Cf. A266493.

Sequence in context: A102194 A102191 A358809 * A285882 A394319 A208184

Adjacent sequences: A266489 A266490 A266491 * A266493 A266494 A266495

Keyword

nonn

Author

R. H. Hardin, Dec 30 2015

Status

approved