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A221287 Equals two maps: number of n X n binary arrays indicating the locations of corresponding elements equal to exactly two of their horizontal and antidiagonal neighbors in a random 0..3 n X n array 0
1, 4, 92, 9107, 4983598, 10344276279 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Diagonal of A221290

LINKS

Table of n, a(n) for n=1..6.

EXAMPLE

Some solutions for n=3

..0..0..0....0..0..1....0..1..0....0..0..0....0..0..1....0..1..1....0..0..1

..1..1..0....1..0..1....0..1..0....1..0..1....0..1..0....0..1..1....1..0..1

..1..1..0....1..1..0....1..1..0....1..0..0....1..1..0....0..1..0....1..0..0

CROSSREFS

Sequence in context: A012071 A012217 A012135 * A177411 A219891 A050878

Adjacent sequences:  A221284 A221285 A221286 * A221288 A221289 A221290

KEYWORD

nonn

AUTHOR

R. H. Hardin Jan 09 2013

STATUS

approved

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Last modified May 18 06:33 EDT 2021. Contains 343994 sequences. (Running on oeis4.)