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A143893 Number of ways of placing kings with no more than 4 mutual attacks on an n X n chessboard symmetric under 180 degree rotation. 2
1, 2, 3, 19, 62, 785, 3961, 92618, 796423, 31554358, 442143014 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..10.

CROSSREFS

Sequence in context: A157042 A128968 A153409 * A262957 A072263 A009178

Adjacent sequences:  A143890 A143891 A143892 * A143894 A143895 A143896

KEYWORD

nonn,more,hard

AUTHOR

R. H. Hardin, Sep 04 2008

STATUS

approved

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Last modified November 21 12:20 EST 2019. Contains 329370 sequences. (Running on oeis4.)