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A145929
Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a tee 1,1 1,2 1,3 2,2 in any orientation.
0
1, 1, 1, 1, 2, 3, 8, 13, 44, 111, 556, 1606, 9677, 40103, 359014, 1871694, 20359902, 143317291, 2226693360, 20614186256, 404517634279, 4951846403553, 133436650402934, 2175520025174634, 76183950538555436, 1636466403191913572
OFFSET
1,5
EXAMPLE
Maximal 8 X 8 example
.0.0.0.0.0.0.0.0
.0.0.0.1.1.1.0.0
.0.0.0.0.1.0.1.0
.0.1.0.0.0.1.1.0
.0.1.1.0.0.0.1.0
.0.1.0.1.0.0.0.0
.0.0.1.1.1.0.0.0
.0.0.0.0.0.0.0.0
CROSSREFS
Sequence in context: A025575 A077055 A327868 * A153865 A369774 A331820
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 25 2008
STATUS
approved