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A185244
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Number of disconnected 4-regular simple graphs on n vertices with girth at least 4.
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17
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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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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 at least g
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FORMULA
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a(n) = A185344(n) - A033886(n) = Euler_transformation(A033886)(n) - A033886(n).
a(n) = A185044(n) + A185245(n).
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CROSSREFS
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4-regular simple graphs with girth at least 4: A033886 (connected), this sequence (disconnected), A185344 (not necessarily connected).
Disconnected 4-regular simple graphs with girth at least g: A033483 (g=3), this sequence (g=4), A185245 (g=5), A185246 (g=6).
Disconnected k-regular simple graphs with girth at least 4: A185214 (any k), A185204 (triangle); specified degree k: A185224 (k=2), A185234 (k=3), this sequence (k=4), A185254 (k=5), A185264 (k=6), A185274 (k=7), A185284 (k=8), A185294 (k=9).
Sequence in context: A202730 A009773 A185044 * A006929 A216613 A215900
Adjacent sequences: A185241 A185242 A185243 * A185245 A185246 A185247
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KEYWORD
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nonn,more,hard
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AUTHOR
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Jason Kimberley, Feb 22 2011
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EXTENSIONS
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a(31) appended by the author once A033886(23) was known, Nov 03 2011
a(31) corrected by the author, Jan 05 2013
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STATUS
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approved
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