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A146681 Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 1100-0111-1100 pattern in any orientation. 0
1, 1, 1, 1, 1, 9, 21, 93, 334, 1347, 5976, 45869, 290540, 3087921, 28902351, 440901387, 5686714599 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

LINKS

Table of n, a(n) for n=1..17.

EXAMPLE

Maximal 8 X 8 example

.0.0.0.1.1.0.0.0

.0.1.0.0.1.1.1.0

.0.1.0.1.1.0.0.0

.1.1.1.0.0.1.0.1

.1.0.1.0.0.1.1.1

.0.0.0.1.1.0.1.0

.0.1.1.1.0.0.1.0

.0.0.0.1.1.0.0.0

CROSSREFS

Sequence in context: A075640 A147480 A146396 * A269633 A279389 A222809

Adjacent sequences:  A146678 A146679 A146680 * A146682 A146683 A146684

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 04 2008

STATUS

approved

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Last modified September 28 17:45 EDT 2022. Contains 357080 sequences. (Running on oeis4.)