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A146159 Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only either as two by three or three by two blocks. 0
1, 1, 1, 1, 7, 15, 60, 184, 747, 3499, 25726, 170389, 1816278, 17509129, 246038108, 3281197739, 66149680918, 1268005261759, 37496297507935, 1034674372954972, 43395951886928470 (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

.1.1.0.1.1.0.0.0

.1.1.0.1.1.0.1.1

.1.1.0.1.1.0.1.1

.0.0.0.0.0.0.1.1

.1.1.0.0.0.0.0.0

.1.1.0.1.1.0.1.1

.1.1.0.1.1.0.1.1

.0.0.0.1.1.0.1.1

CROSSREFS

Sequence in context: A145978 A037376 A141548 * A187986 A039789 A279882

Adjacent sequences:  A146156 A146157 A146158 * A146160 A146161 A146162

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 27 2008

STATUS

approved

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Last modified February 15 22:28 EST 2019. Contains 320138 sequences. (Running on oeis4.)