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Search: id:A143891
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A143891 Number of ways of placing kings with no more than 4 mutual attacks on an n X n chessboard symmetric about the diagonal and under 90 degree rotation. +0
1
1, 2, 1, 5, 2, 15, 7, 68, 23, 370, 104, 2649, 571, 25209, 4176, 313503, 39827, 5212881, 500254, 114569731, 8348616 (list; graph; listen)
OFFSET

0,2
CROSSREFS

Sequence in context: A087123 A097131 A109738 this_sequence A030400 A115345 A140165

Adjacent sequences: A143888 A143889 A143890 this_sequence A143892 A143893 A143894

KEYWORD

nonn

AUTHOR

Ron Hardin (rhhardin(AT)att.net), Sep 04 2008

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Last modified November 29 12:46 EST 2009. Contains 167659 sequences.

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