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A145859
Number of n X n binary arrays symmetric under horizontal and vertical reflection with all ones connected only in two by two blocks.
0
1, 2, 1, 2, 2, 7, 5, 38, 12, 182, 72, 1536, 513, 21327, 4531, 360939, 68662, 9098657, 1429824, 345351393, 40840428, 18058986880, 1747979822, 1362075540043, 106711196102, 149443289019658, 9237029528023, 23324890541218597
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OFFSET
1,2
LINKS
Table of n, a(n) for n=1..28.
EXAMPLE
Maximal 7 X 7 example
.0.0.0.0.0.0.0
.1.1.0.0.0.1.1
.1.1.0.0.0.1.1
.0.0.0.0.0.0.0
.1.1.0.0.0.1.1
.1.1.0.0.0.1.1
.0.0.0.0.0.0.0
CROSSREFS
Sequence in context:
A077014
A093655
A023140
*
A145863
A240492
A110775
Adjacent sequences:
A145856
A145857
A145858
*
A145860
A145861
A145862
KEYWORD
nonn
AUTHOR
R. H. Hardin
, Oct 22 2008
STATUS
approved
