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A146045 Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 2X4 tee 1,1 1,2 1,3 2,3 1,4 in any orientation. 0
1, 1, 1, 5, 17, 49, 267, 1635, 15439, 178481, 2706563, 52897007, 1344799359, 42695435337, 1933850526571, 106233098774339 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Table of n, a(n) for n=1..16.

EXAMPLE

Maximal 8 X 8 example

.0.0.0.0.1.1.1.1

.0.1.0.0.0.1.0.0

.1.1.1.1.0.0.1.0

.0.0.0.0.1.1.1.1

.1.1.1.1.0.0.0.0

.0.1.0.0.1.1.1.1

.0.0.1.0.0.0.1.0

.1.1.1.1.0.0.0.0

CROSSREFS

Sequence in context: A000337 A147260 A273688 * A086866 A054452 A196310

Adjacent sequences:  A146042 A146043 A146044 * A146046 A146047 A146048

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 26 2008

STATUS

approved

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Last modified October 31 00:25 EDT 2020. Contains 338095 sequences. (Running on oeis4.)