A220275 Equals two maps: number of nX2 binary arrays indicating the locations of corresponding elements equal to exactly two of their horizontal, vertical and antidiagonal neighbors in a random 0..1 nX2 array

1, 6, 25, 87, 322, 1168, 4303, 15680, 57251, 209919, 765897, 2798292, 10239771, 37404529, 136700188, 499846884, 1826552660, 6675971458, 24404489928, 89191936887, 325998995843, 1191600903496, 4355213008401, 15918480514002

Offset

1,2

Comments

Column 2 of A220279

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Example

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

Crossrefs

Sequence in context: A164271 A233698 A230723 * A055585 A099625 A209243

Adjacent sequences: A220272 A220273 A220274 * A220276 A220277 A220278

Keyword

nonn

Author

R. H. Hardin Dec 09 2012

Status

approved