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A146011 Number of n X n binary arrays symmetric about the diagonal and under 90 degree rotation with all ones connected only in a 3X3 tee 1,1 1,2 1,3 2,2 3,2 in any orientation. 0
1, 1, 1, 1, 1, 1, 2, 1, 4, 1, 9, 3, 31, 9, 123, 22, 539, 75, 3348, 380, 26210, 2417, 248376, 17011, 2847301, 150387, 41349456, 1725197, 766696111, 24767029 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,7

LINKS

Table of n, a(n) for n=1..30.

EXAMPLE

Maximal 9 X 9 example

.0.0.0.0.0.0.0.0.0

.0.0.0.1.1.1.0.0.0

.0.0.0.0.1.0.0.0.0

.0.1.0.0.1.0.0.1.0

.0.1.1.1.0.1.1.1.0

.0.1.0.0.1.0.0.1.0

.0.0.0.0.1.0.0.0.0

.0.0.0.1.1.1.0.0.0

.0.0.0.0.0.0.0.0.0

CROSSREFS

Sequence in context: A038001 A147080 A146418 * A104620 A243913 A186724

Adjacent sequences:  A146008 A146009 A146010 * A146012 A146013 A146014

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 26 2008

STATUS

approved

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Last modified February 16 15:17 EST 2020. Contains 331961 sequences. (Running on oeis4.)