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A058348
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Number of connected 4-regular simple graphs on n vertices with girth at least 6.
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14
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1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 4, 0, 19, 0, 1272, 25, 494031, 13504
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OFFSET
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0,31
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COMMENTS
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The null graph on 0 vertices is vacuously connected and 4-regular; since it is acyclic, it has infinite girth.
Does a(2n+1) ever exceed a(2n)?
(End)
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LINKS
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CROSSREFS
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Connected k-regular simple graphs with girth at least 6: A186726 (any k), A186716 (triangle); specified degree k: A185116 (k=2), A014374 (k=3), this sequence (k=4).
Connected 4-regular simple graphs with girth at least g: A006820 (g=3), A033886 (g=4), A058343 (g=5), this sequence (g=6).
Connected 4-regular simple graphs with girth exactly g: A184943 (g=3), A184944 (g=4), A184945 (g=5). (End)
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KEYWORD
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nonn,more,hard
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AUTHOR
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EXTENSIONS
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Jason Kimberley inserted Meringer's computed terms a(n)=0 for n in [27,29,31,33] and appended terms a(35) and a(36), by running Meringer's GENREG for 17 and 106 processor days at U. Ncle, on May 04 2010.
a(37) appended from running GENREG for 450 processor days at U. Ncle. by Jason Kimberley, Dec 03 2011
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STATUS
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approved
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