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A146130 Number of n X n binary arrays symmetric about main diagonal with all ones connected only in a 3X2 zee 1,1 1,2 1,3 2,3 2,4 in any orientation. 0
1, 1, 1, 1, 5, 17, 59, 325, 2193, 20593, 247017, 3816169, 76385445, 1998729963, 68606304143, 3070344768595, 178823377788539, 13583194771026533, 1345184891829774733 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

LINKS

Table of n, a(n) for n=1..19.

EXAMPLE

Maximal 8 X 8 example

.0.0.0.0.1.1.1.0

.0.0.1.1.0.0.1.1

.0.1.0.1.1.1.0.0

.0.1.1.0.0.0.1.0

.1.0.1.0.0.0.1.0

.1.0.1.0.0.0.1.1

.1.1.0.1.1.1.0.1

.0.1.0.0.0.1.1.0

CROSSREFS

Sequence in context: A149659 A149660 A149661 * A026619 A142956 A273422

Adjacent sequences:  A146127 A146128 A146129 * A146131 A146132 A146133

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 27 2008

STATUS

approved

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Last modified December 2 11:44 EST 2021. Contains 349440 sequences. (Running on oeis4.)