A220408 Equals two maps: number of 3Xn binary arrays indicating the locations of corresponding elements equal to exactly two of their horizontal, diagonal and antidiagonal neighbors in a random 0..1 3Xn array

1, 23, 122, 908, 6013, 41510, 273253, 1851686, 12276677, 82620823, 550113999, 3691113431, 24624350056, 164959794914

Offset

1,2

Comments

Row 3 of A220406

Links

Table of n, a(n) for n=1..14.

Example

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

Crossrefs

Sequence in context: A293565 A362569 A099068 * A044355 A044736 A033211

Adjacent sequences: A220405 A220406 A220407 * A220409 A220410 A220411

Keyword

nonn

Author

R. H. Hardin Dec 13 2012

Status

approved