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 A185044 Number of disconnected 4-regular simple graphs on n vertices with girth exactly 4. 5
 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,19 COMMENTS 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. LINKS FORMULA a(n) = A185244(n) - A185245(n). a(n) = A185144(n) - A184944(n). CROSSREFS 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 KEYWORD nonn,hard,more AUTHOR Jason Kimberley, Nov 04 2011 EXTENSIONS a(31) corrected by the author, propagated from A185244, Jan 05 2013 STATUS approved

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Last modified September 30 18:12 EDT 2020. Contains 337440 sequences. (Running on oeis4.)