A265677 Number of nX2 arrays containing 2 copies of 0..n-1 with no equal vertical or antidiagonal neighbors and new values introduced sequentially from 0.

1, 1, 4, 23, 209, 2301, 29992, 450525, 7666097, 145748085, 3062086652, 70451319403, 1761725152737, 47575849111097, 1379912569740752, 42782608276446713, 1411969570132526241, 49423093937535984041

Offset

1,3

Comments

Column 2 of A265679.

Links

Table of n, a(n) for n=1..18.

Example

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

Crossrefs

Cf. A265679.

Sequence in context: A099869 A369194 A365353 * A221371 A056785 A188404

Adjacent sequences: A265674 A265675 A265676 * A265678 A265679 A265680

Keyword

nonn

Author

R. H. Hardin, Dec 13 2015

Status

approved