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A228500 Number of n X n binary arrays with top left value 1 and no two ones adjacent horizontally, vertically, diagonally or antidiagonally. 1
1, 1, 12, 87, 2002, 59839, 3862849, 405580157, 81304395949, 28446567810005, 18268841726936268, 20937720031330292269, 43502129718103134992611, 162426195975365708781849519, 1095156092719874995442597502324 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Diagonal of A228506

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..29

EXAMPLE

Some solutions for n=4

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

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

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

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

CROSSREFS

Sequence in context: A180797 A137207 A206765 * A082814 A178257 A057406

Adjacent sequences:  A228497 A228498 A228499 * A228501 A228502 A228503

KEYWORD

nonn

AUTHOR

R. H. Hardin Aug 23 2013

STATUS

approved

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Last modified February 26 14:39 EST 2021. Contains 341632 sequences. (Running on oeis4.)