A220938 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..2 4Xn array

1, 37, 556, 9107, 172904, 2876430, 49406891

Offset

1,2

Comments

Row 4 of A220935

Links

Table of n, a(n) for n=1..7.

Example

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

Crossrefs

Sequence in context: A006303 A219440 A219141 * A221292 A231514 A156226

Adjacent sequences: A220935 A220936 A220937 * A220939 A220940 A220941

Keyword

nonn

Author

R. H. Hardin Dec 25 2012

Status

approved