A220409 Equals two maps: number of 4Xn binary arrays indicating the locations of corresponding elements equal to exactly two of their horizontal, diagonal and antidiagonal neighbors in a random 0..1 4Xn array

1, 78, 720, 10989, 128448, 1701214, 20736643, 263993960

Offset

1,2

Comments

Row 4 of A220406

Links

Table of n, a(n) for n=1..8.

Example

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

Crossrefs

Sequence in context: A057806 A057803 A126994 * A129238 A297759 A147619

Adjacent sequences: A220406 A220407 A220408 * A220410 A220411 A220412

Keyword

nonn

Author

R. H. Hardin Dec 13 2012

Status

approved