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Search: id:A086663
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| A086663 |
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Number of non-attacking knights on a n*n board with all non-perimeteral squares removed. |
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+0
1
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| 1, 4, 4, 8, 12, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52, 56, 60, 64, 68, 72, 76, 80, 84, 88, 92, 96, 100, 104, 108, 112, 116, 120, 124, 128, 132, 136, 140, 144, 148, 152, 156, 160, 164, 168, 172, 176, 180, 184, 188, 192, 196, 200, 204, 208, 212, 216, 220, 224, 228
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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The basic maximal arrangement is with a knight in each corner and any centers of edges. The remaining 16 squares are coupled together, so only half may be used.
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FORMULA
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a(n)=4*(n-3) for n>5
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EXAMPLE
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One of the maximal arrangements for a(8):
k-kkkk-k
-......-
k......k
k......k
k......k
k......k
-......-
k-kkkk-k
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PROGRAM
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(PARI) a(n)=local(r); r=4+4*max(0, n-6); if (n>3, r+=8); if (n==4, r-=4); r for (i=2, 40, print1(a(i)", "))
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CROSSREFS
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Sequence in context: A014687 A152967 A004024 this_sequence A003829 A002368 A022087
Adjacent sequences: A086660 A086661 A086662 this_sequence A086664 A086665 A086666
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KEYWORD
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nonn,easy
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AUTHOR
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Jon Perry (perry(AT)globalnet.co.uk), Jul 27 2003
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EXTENSIONS
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More terms from David Wasserman (wasserma(AT)spawar.navy.mil), Mar 28 2005
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