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A145932 Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a tee 1,1 1,2 1,3 2,2 in any orientation. 0
1, 1, 1, 5, 20, 85, 428, 3123, 34838, 454719, 8335296, 187056538, 6169076015, 247329264689, 14010937295624, 978281276679416, 99281241941019762, 12290336204514423117 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Table of n, a(n) for n=1..18.

EXAMPLE

Maximal 8 X 8 example

.1.1.1.0.0.1.1.1

.0.1.0.0.0.0.1.0

.0.0.0.1.1.1.0.1

.1.0.0.0.1.0.1.1

.1.1.0.1.0.0.0.1

.1.0.1.1.1.0.0.0

.0.1.0.0.0.0.1.0

.1.1.1.0.0.1.1.1

CROSSREFS

Sequence in context: A152187 A341920 A045499 * A026661 A099014 A219672

Adjacent sequences:  A145929 A145930 A145931 * A145933 A145934 A145935

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 25 2008

STATUS

approved

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Last modified July 26 20:17 EDT 2021. Contains 346294 sequences. (Running on oeis4.)