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A146128 Number of n X n binary arrays symmetric under horizontal reflection 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, 9, 13, 45, 103, 3361, 8833, 372663, 1287127, 106100985, 471171193, 109709730093, 638573372655, 304442910936313, 2309148561615411, 2461266528050264151, 24325578567487185537, 57639766702959393452219 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

LINKS

Table of n, a(n) for n=1..21.

EXAMPLE

Maximal 8 X 8 example

.0.1.0.0.0.0.1.0

.1.1.0.0.0.0.1.1

.1.0.0.0.0.0.0.1

.1.0.0.0.0.0.0.1

.0.0.1.0.0.1.0.0

.0.0.1.0.0.1.0.0

.0.1.1.0.0.1.1.0

.0.1.0.0.0.0.1.0

CROSSREFS

Sequence in context: A160117 A068984 A146016 * A146039 A270234 A270718

Adjacent sequences:  A146125 A146126 A146127 * A146129 A146130 A146131

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 27 2008

STATUS

approved

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Last modified February 17 17:47 EST 2019. Contains 320222 sequences. (Running on oeis4.)