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A144059
Number of n X n binary arrays, symmetric under 180 degree rotation, with every 1 adjacent to at least one other 1, but at most one 1 adjacent horizontally and at most one 1 adjacent vertically.
0
1, 2, 7, 43, 317, 4395, 85883, 3189035, 155707292, 14992855085, 1844750664909, 446183107764907, 140966932321586720
OFFSET
1,2
CROSSREFS
Sequence in context: A146759 A303031 A220220 * A352293 A078676 A265229
KEYWORD
nonn
AUTHOR
R. H. Hardin, Sep 08 2008
STATUS
approved