

A185244


Number of disconnected 4regular simple graphs on n vertices with girth at least 4.


17



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


LINKS

Table of n, a(n) for n=0..31.
Jason Kimberley, Index of sequences counting disconnected kregular simple graphs with girth at least g


FORMULA

a(n) = A185344(n)  A033886(n) = Euler_transformation(A033886)(n)  A033886(n).
a(n) = A185044(n) + A185245(n).


CROSSREFS

4regular simple graphs with girth at least 4: A033886 (connected), this sequence (disconnected), A185344 (not necessarily connected).
Disconnected 4regular simple graphs with girth at least g: A033483 (g=3), this sequence (g=4), A185245 (g=5), A185246 (g=6).
Disconnected kregular simple graphs with girth at least 4: A185214 (any k), A185204 (triangle); specified degree k: A185224 (k=2), A185234 (k=3), this sequence (k=4), A185254 (k=5), A185264 (k=6), A185274 (k=7), A185284 (k=8), A185294 (k=9).
Sequence in context: A202730 A009773 A185044 * A006929 A216613 A215900
Adjacent sequences: A185241 A185242 A185243 * A185245 A185246 A185247


KEYWORD

nonn,more,hard


AUTHOR

Jason Kimberley, Feb 22 2011


EXTENSIONS

a(31) appended by the author once A033886(23) was known, Nov 03 2011
a(31) corrected by the author, Jan 05 2013


STATUS

approved



