A221292 Equals two maps: number of 4Xn binary arrays indicating the locations of corresponding elements equal to exactly two of their horizontal and antidiagonal neighbors in a random 0..3 4Xn array.

1, 37, 556, 9107, 172904, 2890017, 49684593, 821323042, 13475380990

Offset: 1

Author

R. H. Hardin Jan 09 2013

Keywords

• nonn

Comments

Row 4 of A221290

Examples

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