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A146646 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 1010-1111-1000 pattern in any orientation. 0
1, 1, 1, 1, 1, 1, 1, 1, 7, 13, 27, 41, 115, 303, 1555, 4709, 23865, 76741, 449473, 1923409, 15857735, 84725491 (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

.0.0.0.1.0.0.0.0.0

.0.0.0.1.1.1.1.0.0

.0.0.0.1.0.1.0.1.0

.1.1.1.0.0.0.1.1.0

.0.1.0.0.0.0.0.1.0

.0.1.1.0.0.0.1.1.1

.0.1.0.1.0.1.0.0.0

.0.0.1.1.1.1.0.0.0

.0.0.0.0.0.1.0.0.0

CROSSREFS

Sequence in context: A067870 A147258 A146718 * A096194 A160889 A283650

Adjacent sequences:  A146643 A146644 A146645 * A146647 A146648 A146649

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 04 2008

STATUS

approved

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Last modified September 29 09:23 EDT 2022. Contains 357088 sequences. (Running on oeis4.)