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A146827 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 1000-1111-0100-0100 pattern in any orientation. 0
1, 1, 1, 1, 1, 1, 1, 1, 5, 9, 21, 33, 75, 191, 769, 2241, 10975, 33339, 159399, 627233, 4142099, 21519301 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,9

LINKS

Table of n, a(n) for n=1..22.

EXAMPLE

Maximal 9 X 9 example

.0.0.0.0.1.1.0.0.0

.0.0.1.1.1.0.0.0.0

.0.1.0.0.1.0.0.0.0

.0.1.0.0.1.0.0.0.1

.1.1.1.1.0.1.1.1.1

.1.0.0.0.1.0.0.1.0

.0.0.0.0.1.0.0.1.0

.0.0.0.0.1.1.1.0.0

.0.0.0.1.1.0.0.0.0

CROSSREFS

Sequence in context: A273486 A146867 A068481 * A297360 A216414 A147018

Adjacent sequences:  A146824 A146825 A146826 * A146828 A146829 A146830

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 04 2008

STATUS

approved

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Last modified November 27 07:28 EST 2021. Contains 349365 sequences. (Running on oeis4.)