A265879 Number of nX2 arrays containing 2 copies of 0..n-1 with no element plus any horizontal neighbor equal to n-1.

0, 2, 24, 792, 39360, 2396880, 241012800, 27159592320, 4466274785280, 806760393465600, 197138895617664000, 52164067053271219200

Offset

1,2

Comments

Column 2 of A265882.

Links

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

Example

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

Crossrefs

Cf. A265882.

Sequence in context: A292694 A012128 A099704 * A339946 A172492 A322895

Adjacent sequences: A265876 A265877 A265878 * A265880 A265881 A265882

Keyword

nonn

Author

R. H. Hardin, Dec 17 2015

Status

approved