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A146034 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 3X3 el 1,1 1,2 1,3 2,3 3,3 in any orientation. 0
1, 1, 1, 3, 3, 7, 15, 43, 83, 271, 633, 3283, 9541, 54293, 204827, 1408893, 6437305, 54681853, 303651861, 3282191633, 22628378377, 297350762879, 2544553561975, 41024771076465, 431789004830701, 8608866149320377, 111456693040140865 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Table of n, a(n) for n=1..27.

EXAMPLE

Maximal 8 X 8 example

.0.0.1.0.0.1.1.1

.0.0.1.0.1.0.0.1

.1.1.1.0.1.0.0.1

.0.0.0.0.1.1.1.0

.0.1.1.1.0.0.0.0

.1.0.0.1.0.1.1.1

.1.0.0.1.0.1.0.0

.1.1.1.0.0.1.0.0

CROSSREFS

Sequence in context: A004043 A104176 A032294 * A032029 A058571 A058492

Adjacent sequences:  A146031 A146032 A146033 * A146035 A146036 A146037

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 26 2008

STATUS

approved

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Last modified October 26 16:34 EDT 2020. Contains 338027 sequences. (Running on oeis4.)