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A143870
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Number of ways of placing kings with no more than 1 mutual attack on an n X n chessboard.
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6
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1, 2, 11, 91, 1462, 38483, 1755113, 140404442, 19400886875, 4764856837927, 2050537030592506, 1572046460892726633, 2133798146501117397613, 5167591018292995062973870, 22288638410038000574365307819, 171813750317653145879779979300275, 2366759768251260378737273078723819964
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OFFSET
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0,2
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LINKS
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EXAMPLE
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Configurations of 0,1,2,3 or 4 kings on an 2 X 2 chessboard and the number of mutual attacks:
.. .. .. K. .K .. K. KK .K .K K. K. .K KK KK KK
.. K. .K .. .. KK K. .. .K K. .K KK KK .K K. KK
0 0 0 0 0 1 1 1 1 1 1 3 3 3 3 6
From 16 configurations is 11 with no more than 1 mutual attack, a(2)=11.
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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