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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

Table of n, a(n) for n=0..31.

Jason Kimberley, Index of sequences counting disconnected k-regular simple graphs with girth exactly g

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: A202730 A009773 * A185244 A006929 A216613 A215900

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 April 23 17:46 EDT 2014. Contains 240946 sequences.