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A143882
Number of ways of placing kings with no more than 3 mutual attacks on an n X n chessboard symmetric under horizontal reflection.
1
1, 2, 3, 29, 48, 1401, 1825, 183270, 194391, 76221979, 59133738, 86201358557, 54181631319, 318503225414986, 146475713866791
OFFSET
0,2
CROSSREFS
Sequence in context: A214889 A137472 A065932 * A108657 A116325 A228021
KEYWORD
nonn,more,hard
AUTHOR
R. H. Hardin, Sep 04 2008
STATUS
approved