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A144244
Number of n X n binary arrays, symmetric under 180 degree rotation, with every 1 adjacent to at least one other 1 both bishopwise and rookwise but with no three 1s in a row bishopwise or rookwise.
0
1, 2, 1, 9, 24, 94, 870, 7731, 58940, 1518701, 25116276, 780979887, 31966477480
OFFSET
1,2
CROSSREFS
Sequence in context: A221756 A094633 A261060 * A079582 A259872 A320534
KEYWORD
nonn
AUTHOR
R. H. Hardin, Sep 15 2008
STATUS
approved