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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
OFFSET
1,5
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
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 27 2008
STATUS
approved