

A185044


Number of disconnected 4regular 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
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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 kregular simple graphs with girth exactly g


FORMULA

a(n) = A185244(n)  A185245(n).
a(n) = A185144(n)  A184944(n).


CROSSREFS

Disconnected 4regular simple graphs with girth exactly g: A185043 (g=3), this sequence (g=4).
Disconnected kregular 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



