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A145950 Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected in a 3X2 elbow 1,1 1,2 1,3 2,3 in any orientation. 0
1, 1, 1, 9, 31, 205, 1307, 12227, 171281, 3266929, 85166971, 3120438693, 149314103237, 10059913232521, 894685834014771 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Table of n, a(n) for n=1..15.

EXAMPLE

Maximal 8 X 8 example

.0.0.0.1.1.0.1.1

.1.0.0.1.0.1.0.1

.1.0.0.1.0.1.0.1

.1.1.0.0.1.1.0.0

.0.0.1.1.0.0.1.1

.1.0.1.0.1.0.0.1

.1.0.1.0.1.0.0.1

.1.1.0.1.1.0.0.0

CROSSREFS

Sequence in context: A140323 A160653 A189436 * A177743 A266710 A159279

Adjacent sequences:  A145947 A145948 A145949 * A145951 A145952 A145953

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 25 2008

STATUS

approved

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Last modified July 6 23:01 EDT 2020. Contains 335484 sequences. (Running on oeis4.)