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A185044
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Number of disconnected 4-regular simple graphs on n vertices with girth exactly 4.
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5
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 2, 2, 15, 35, 247, 1692, 17409, 197924, 2492824, 33117880, 461597957, 6709514218, 101153412903, 1597440868898
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OFFSET
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0,19
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COMMENTS
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Only one component need have girth exactly four; the other components need only have girth at least four.
First differs from A185244 at n = 38, the smallest n where A185245 is nonzero.
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LINKS
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Table of n, a(n) for n=0..31.
Jason Kimberley, Index of sequences counting disconnected k-regular simple graphs with girth exactly g
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FORMULA
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a(n) = A185244(n) - A185245(n).
a(n) = A185144(n) - A184944(n).
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CROSSREFS
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Disconnected 4-regular simple graphs with girth exactly g: A185043 (g=3), this sequence (g=4).
Disconnected k-regular simple graphs with girth exactly 4: A185034 (k=3), this sequence (k=4).
Sequence in context: A273319 A009773 A325912 * A185244 A329920 A006929
Adjacent sequences: A185041 A185042 A185043 * A185045 A185046 A185047
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KEYWORD
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nonn,hard,more
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AUTHOR
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Jason Kimberley, Nov 04 2011
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EXTENSIONS
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a(31) corrected by the author, propagated from A185244, Jan 05 2013
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STATUS
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approved
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