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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: A009773 A325912 A365086 * A185244 A329920 A006929
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 March 19 06:50 EDT 2024. Contains 370953 sequences. (Running on oeis4.)