A220960 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..3 3Xn array

1, 23, 142, 1769, 15640, 135445, 1135785, 9319689, 75739525, 610550298, 4906067283, 39329548159, 314985289528, 2521161457137

Offset

1,2

Comments

Row 3 of A220959

Links

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

Example

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

Crossrefs

Sequence in context: A036494 A185098 A220796 * A376891 A139175 A055827

Adjacent sequences: A220957 A220958 A220959 * A220961 A220962 A220963

Keyword

nonn

Author

R. H. Hardin Dec 26 2012

Status

approved